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Feasibility of Neural Stimulation With Floating-Light-Activated Microelectrical Stimulators
Ammar Abdo; Mesut Sahin
Neural microstimulation is becoming a powerful tool for the restoration of impaired functions in the central nervous system. Microelectrode arrays with fine wire interconnects have traditionally been used in the development of these neural pros- thetic devices. However, these interconnects are usually the most vulnerable part of the neuroprosthetic implant that can eventually causethedevicetofail.Inthispaper,weinvestigatethefeasibilityof floating-light-activated microelectrical stimulators (FLAMES) for wireless
Floating light-activated microelectrical stimulators tested in the rat spinal cord
NASA Astrophysics Data System (ADS)
Abdo, Ammar; Sahin, Mesut; Freedman, David S.; Cevik, Elif; Spuhler, Philipp S.; Unlu, M. Selim
Microelectrodes of neural stimulation utilize fine wires for electrical connections to driving electronics. Breakage of these wires and the neural tissue response due to their tethering forces are major problems encountered with long-term implantation of microelectrodes. The lifetime of an implant for neural stimulation can be substantially improved if the wire interconnects are eliminated. Thus, we proposed a floating light-activated microelectrical stimulator (FLAMES) for wireless neural stimulation. In this paradigm, a laser beam at near infrared (NIR) wavelengths will be used as a means of energy transfer to the device. In this study, microstimulators of various sizes were fabricated, with two cascaded GaAs p-i-n photodiodes, and tested in the rat spinal cord. A train of NIR pulses (0.2 ms, 50 Hz) was sent through the tissue to wirelessly activate the devices and generate the stimulus current. The forces elicited by intraspinal stimulation were measured from the ipsilateral forelimb with a force transducer. The largest forces were around 1.08 N, a significant level of force for the rat forelimb motor function. These in vivo tests suggest that the FLAMES can be used for intraspinal microstimulation even for the deepest implant locations in the rat spinal cord. The power required to generate a threshold arm movement was investigated as the laser source was moved away from the microstimulator. The results indicate that the photon density does not decrease substantially for horizontal displacements of the source that are in the same order as the beam radius. This gives confidence that the stimulation threshold may not be very sensitive to small displacement of the spinal cord relative to the spine-mounted optical power source.
Floating Light-Activated Micro Electrical Stimulators Tested in the Rat Spinal Cord
Abdo, Ammar; Sahin, Mesut; Freedman, David S.; Cevik, Elif; Spuhler, Philipp S.; Unlu, M. Selim
Microelectrodes of neural stimulation utilize fine wires for electrical connections to driving electronics. Breakage of these wires and the neural tissue response due to their tethering forces are major problems encountered with long term implantation of microelectrodes. The lifetime of an implant for neural stimulation can be substantially improved if the wire interconnects are eliminated. Thus, we proposed a floating light-activated micro electrical stimulator (FLAMES) for wireless neural stimulation. In this paradigm, a laser beam at near infrared (NIR) wavelengths will be used as a means of energy transfer to the device. In this study, microstimulators of various sizes were fabricated, with two cascaded GaAs p-i-n photodiodes, and tested in the rat spinal cord. A train of NIR pulses (0.2 ms, 50 Hz) was sent through the tissue to wirelessly activate the devices and generate the stimulus current. The forces elicited by intraspinal stimulation were measured from the ipsilateral forelimb with a force transducer. The largest forces were around 1.08N, a significant level of force for the rat forelimb motor function. These in vivo tests suggest that the FLAMES can be used for intraspinal microstimulation even for the deepest implant locations in the rat spinal cord. The power required to generate a threshold arm movement was investigated as the laser source was moved away from the microstimulator. The results indicate that the photon density does not decrease substantially for horizontal displacements of the source that are in the same order as the beam radius. This gives confidence that the stimulation threshold may not be very sensitive to small displacement of the spinal cord relative to the spine-mounted optical power source. PMID:21914931
Floating light-activated microelectrical stimulators tested in the rat spinal cord This article has been downloaded from IOPscience. Please scroll down to see the full text article.
Floating light-activated microelectrical stimulators tested in the rat spinal cord This article has in the rat spinal cord Ammar Abdo1, Mesut Sahin1,4, David S Freedman2, Elif Cevik3, Philipp S Spuhler3 and M spinal cord. A train of NIR pulses (0.2 ms, 50 Hz) was sent through the tissue to wirelessly activate
Floating point verification in HOL Light: the exponential function
Haddadi, Hamed
Floating point verification in HOL Light: the exponential function John Harrison \\Lambda University in floating point arithmetic seem good targets for formal verification using a me chanical theorem prover. Wechecked verification of an algorithm for computing the exponential function in IEEE754 standard binary floating point
FLOATING PLANT AND MARINE ACTIVITIES Table Of Contents
US Army Corps of Engineers
EM 385-1-1 XX Sep 13 i Section 19 FLOATING PLANT AND MARINE ACTIVITIES Table Of Contents Section-1 SECTION 19 FLOATING PLANT and MARINE ACTIVITIES 19.A GENERAL 19.A.01 Floating plant inspection and certification. a. All floating plant regulated by the USCG shall have required USCG documentation
Stochastic modeling of light-weight floating objects
Zhi Yuan; Fan Chen; Ye Zhao
Light-weight objects floating inside a flow play a significant role in the liveliness of our world (e.g., leaves, dust, snowflakes, bubbles). They follow the flow and show complex and chaotic motion. First, animators usually add simple random noise to the streaming path. However, this method yields low-quality floating behavior since the random noise does not take into account the spatial
Broad-band, lossless monolithic microwave active floating inductor
Guang Fei Zhang; J. L. Gautier
A broadband, lossless microwave active floating inductor is proposed for general use in monolithic microwave integrated circuits. The attractive features of this active floating inductor are that (1) it is lossless, (2) it can operate over a wide microwave frequency range, (3) its size is independent of the inductance value, and (4) it can be easily made using MMIC technology
Charge retention characteristics of silicide-induced crystallized polycrystalline silicon floating gate thin-film transistors for active matrix organic light-emitting diode.
Park, Jae Hyo; Son, Se Wan; Byun, Chang Woo; Kim, Hyung Yoon; Joo, So Na; Lee, Yong Woo; Yun, Seung Jae; Joo, Seung Ki
In this work, non-volatile memory thin-film transistor (NVM-TFT) was fabricated by nickel silicide-induced laterally crystallized (SILC) polycrystalline silicon (poly-Si) as the active layer. The nickel seed silicide-induced crystallized (SIC) poly-Si was used as storage layer which is embedded in the gate insulator. The novel unit pixel of active matrix organic light-emitting diode (AMOLED) using NVM-TFT is proposed and investigated the electrical and optical performance. The threshold voltage shift showed 17.2 V and the high reliability of retention characteristic was demonstrated until 10 years. The retention time can modulate the recharge refresh time of the unit pixel of AMOLED up to 5000 sec. PMID:24245194
CMOS Active-Pixel Image Sensor With Simple Floating Gates
NASA Technical Reports Server (NTRS)
Fossum, Eric R.; Nakamura, Junichi; Kemeny, Sabrina E.
Experimental complementary metal-oxide/semiconductor (CMOS) active-pixel image sensor integrated circuit features simple floating-gate structure, with metal-oxide/semiconductor field-effect transistor (MOSFET) as active circuit element in each pixel. Provides flexibility of readout modes, no kTC noise, and relatively simple structure suitable for high-density arrays. Features desirable for "smart sensor" applications.
Active motion and load control of floating offshore wind turbines
NASA Astrophysics Data System (ADS)
Jalili, Kaveh
The research in this thesis is focused on stabilization and load reduction of floating offshore wind turbine (FOWT) structures for both the fore-aft (pitch) and side-to-side (roll) directions. Based on the Tuned Mass Damper (TMD) and Active Vane concepts recently proposed, two composite actuation schemes are investigated. The first scheme is to apply the horizontal vane and vertical vane to platform pitch and roll, respectively, resulting in the so-called Double Vane Actuation (DVA) scheme. The second scheme is the combination of the TMD based pitch control and active vertical vane based roll control, resulting in the so-called Hybrid Actuation (HA) scheme. Simulation results of DVA show great reductions of motions and loads in the fore-aft and side-to-side directions. Performance of HA is investigated by extensive simulations based on the IEC61400-3 standard and results show significant and consistent motions and loads reductions in both FA and SS directions.
Endocytotic activity of the free floating cells and epithelial cells in the endolymphatic sac: an electron microscopic study.
Fukazawa, K; Sakagami, M; Matsunaga, T; Fujita, H
The fine structure and its functional properties of both free floating cells and epithelial cells in the endolymphatic sac after injections of India ink particles or polystyrene latex beads, 0.24 micron in diameter, into the endolymphatic space, were studied using light and electron microscopy. Twenty-four to 48 hours after injections, these foreign materials had accumulated in the lumen of the endolymphatic sac and a large number of them were ingested into free floating cells, most of which appear to be macrophages. Granular leucocytes taking up the foreign materials into the cytoplasm were also recognized in the sac lumen. A few of these leucocytes passed through the epithelium and migrated to the subepithelial connective tissue, while the others were degenerated and phagocytosed by the free floating cells in the lumen of the sac. In addition to the free floating cells, ink particles, latex beads, and degenerated leucocytes were endocytosed into some of the epithelial cells. As we reported previously, the epithelial cells were clearly classified into two types; type-1 epithelial cells (cytoorganelle-rich cells) and type-2 epithelial cells (filament-rich cells). The foreign materials and degenerated cells were taken up mainly into the type-1 epithelial cells, while the type-2 epithelial cells did not show so marked endocytotic activity in comparison with the type-1 epithelial cells. Thus, it becomes clear that the endolymphatic sac plays an important role in the endocytotic activity for foreign materials and waste products, and both the free floating cells and the type-1 epithelial cells of the sac have strong endocytotic activity. PMID:1867416
A Tunable Lossless HBT Broad-Band Monolithic Microwave Floating Active Inductor
C. Zanchi; T. Parra; J. Graffeujil
A monolithic floating Tunable Active Inductor (TAI) based on an Heterojunction Bipolar Transistor design is proposed. This circuit is composed of a common emitter cascode HBT and a feedback common base one. Additionally to its lossless and broad-band characteristics, this HBT active inductor features a voltage controlled tuning capability both for the inductance value and for the operating frequency range.
Correlative light and electron microscopy for a free-floating spindle in Xenopus laevis egg extracts.
Tranfield, Erin M; Heiligenstein, Xavier; Peristere, Ina; Antony, Claude
Cryoimmobilization is an optimal method of preserving sample ultrastructure in electron microscopy studies. However, cryoimmobilization is limited to thin samples and this limitation may necessitate the isolation of the structure of interest. For cellular structures that are found in low number, or only during certain phases of the cell cycle, an added benefit of isolation is the possibility to concentrate the structures. We developed a method to perform correlative light and electron microscopy on infrequent isolated subcellular structures. In this chapter, we will describe our protocol that uses a combination of existing techniques and new solutions for the isolation, identification, cryoimmobilization, targeted ultramicrotomy, and imaging of the free-floating meiotic spindles assembled in Xenopus laevis egg extract. PMID:25287839
NSDL National Science Digital Library
Thomas, Fred
In this lesson from Math Machines, students will design and test an automatic control system for lighting a room. They will examine the system's energy efficiency, response time and effectiveness. Students will be led through the activity step by step via the provided handout. A participant handout (including worksheets), facilitator notes, construction guide, sample data and annotated program listing are made available for download. Links to calculator programs are also included.
ERIC Educational Resources Information Center
Waugh, Michael
The purpose of this article is to describe a simple laboratory activity in which students collect a series of measurements and then use graphical analysis to determine the nature of the relationship between an object's mass and the volume of water it displaces. In this activity, students explore the relationships between the mass of a floating�
NSDL National Science Digital Library
Fresno Community Science Workshop
In this activity, learners create a cool floating animal using the science of magnetism. Learners discover what happens when a piece of magnetic metal enters a magnet's field. Learners also examine magnetic poles. Note, a drill is required for this activity, and is not included in the cost of materials.
Development of a self floating slow release formulation of Bacillus thuringiensis var. israelensis and its larvicidal activity.
Prabakaran, G; Padmanabhan, V; Balaraman, K
Alginate encapsulated B. thuringiensis var. israelensis (B. t. i.) self floating type formulations were prepared. Its spore release rate, floating efficacy and larvicidal activity against Culex quinquefasiatus were tested in the laboratory. The larval mortality of 91-100% was induced by the floating formulation with a mean spore release of 3.04 x 10(4)/ml/day from 6th day to 27th day. From day 28 to 33 the mean number of spores released were 1.16 x 10(4)/ml/day which caused 72.2-88.2% mortality. From 34th day to 40th day the mean number of spores released were 4.97 x 10(3)/ml/day which caused 42.2-67.2% mortality. However, the self floating alginate encapsulated beads were intact and found to float upto 40 days. PMID:11349533
NSDL National Science Digital Library
This is a lesson about displacement, buoyancy, and density. Learners will understand why ice floats. Includes background information, teacher notes, assessment criteria, and related resources; activities are differentiated for Pre-K-grade 2 and grades 3-5. This is lesson 4 of the unit Exploring Ice in the Solar System.
NSDL National Science Digital Library
Thomas, Fred
In this lesson from Math Machines, students will learn a practical application of the law of reflection. The class will program a SAM robot to pivot a mirror and reflect a light source. In addition to learning about robotics and gaining experience programming calculators, the students will also get to see geometry applied in a real world experiment. A participant handout (including worksheet) and facilitator notes are made available for download in DOC file format. Links to calculator programs are also included.
NSDL National Science Digital Library
Michael Waugh
The purpose of this article is to describe a simple laboratory activity in which students collect a series of measurements and then use graphical analysis to determine the nature of the relationship between an object's mass and the volume of water it displaces. In this activity, students explore the relationships between the mass of a floating object, the amount the object sinks in the water, and its displaced volume. The data will reveal a unique relationship between an object's metrically measured mass and volume and its buoyancy in water. This can lead to an elaboration of the density concept and provide a concrete model for systems involving other forms of balance and equilibrium.
Gangion Floats Type* Type* Weights Type* Monitored Hooks / section Total sections Deployed Retrieved in comments #12;Bait Light devices Species 0 None 3 Glow bead kg 1 4 Other 2 Battery light Y / N Y / N Other
HAWC Response to Lighting Activity
NASA Astrophysics Data System (ADS)
Lara, A.
The High Altitude Water Cherenkov (HAWC) observatory is being constructed at the Sierra Negra volcano (4100 m a.s.l.) in Mexico. HAWC's primary purpose is the study of both: galactic and extra-galactic sources of high energy gamma rays. HAWC will consist of 300 large water Cherenkov detectors (WCD), each instrumented with 4 photo-multipliers (PMTs). The Data taking has already started while construction continues, with the completion projected for late 2014. The HAWC scaler system records the rates of individual PMTs giving the opportunity of study relatively low energy transients as solar energetic particles and the solar modulation of galactic cosmic rays. In this work, we present the observations of scaler rate enhancements associated with lightning activity observed close to HAWC (i. e. at high altitude). In particular, we present the time and space coincidence of the lighting strikes and the scaler enhancements and our preliminary speculations on the origin of the detector response to the lighting activity.
Time(24-hr) Hooks Branchline Floats
(m) Seabird Mitigation HaulDir. Begin . End . Begin . F End . R Hooks Branchline Floats Type* # Float line Type* Measured length Weight (g) Shark line on floats? Hook type* Total set *relate to Types described Other explain in comments #12;Bait Light devices Species 0 None 3 Glow bead kg 1 4 Other Hook No. 2
Bright light activates a trigeminal nociceptive pathway
Okamoto, Keiichiro; Tashiro, Akimasa; Chang, Zheng; Bereiter, David A.
Bright light can cause ocular discomfort and/or pain; however, the mechanism linking luminance to trigeminal nerve activity is not known. In this study we identify a novel reflex circuit necessary for bright light to excite nociceptive neurons in superficial laminae of trigeminal subnucleus caudalis (Vc/C1). Vc/C1 neurons encoded light intensity and displayed a long delay (>10 s) for activation. Microinjection of lidocaine into the eye or trigeminal root ganglion (TRG) inhibited light responses completely, whereas topical application onto the ocular surface had no effect. These findings indicated that light-evoked Vc/C1 activity was mediated by an intraocular mechanism and transmission through the TRG. Disrupting local vasomotor activity by intraocular microinjection of the vasoconstrictive agents, norepinephrine or phenylephrine, blocked light-evoked neural activity, whereas ocular surface or intra-TRG microinjection of norepinephrine had no effect. Pupillary muscle activity did not contribute since light-evoked responses were not altered by atropine. Microinjection of lidocaine into the superior salivatory nucleus diminished light-evoked Vc/C1 activity and lacrimation suggesting that increased parasympathetic outflow was critical for light-evoked responses. The reflex circuit also required input through accessory visual pathways since both Vc/C1 activity and lacrimation were prevented by local blockade of the olivary pretectal nucleus. These findings support the hypothesis that bright light activates trigeminal nerve activity through an intraocular mechanism driven by a luminance-responsive circuit and increased parasympathetic outflow to the eye. PMID:20206444
Even Light Activity Can Boost Seniors' Health
... nih.gov/medlineplus/news/fullstory_153175.html Even Light Activity Can Boost Seniors' Health Researchers suggest 300 ... 2015 FRIDAY, June 19, 2015 (HealthDay News) -- Regular light exercise can be as good for seniors as ...
NSDL National Science Digital Library
WGBH Boston
In this activity, challenge learners to float a paper clip in a cup of water. Learners discover that a paper clip will sink in a cup of water, except when it is placed on a piece of paper towel. Use this activity to demonstrate the principles of surface tension, adhesion/cohesion, and gravity.
Biagioni, Edoardo S.
Overview o floating point - SPARC double floats - SPARC quad floats - Intel coprocessor - Intel formats - Intel operations o processor; SPARC 64-bit Floating Point Representation o 1 bit for the sign s (0
Artificial light and nocturnal activity in gammarids.
Perkin, Elizabeth K; H�lker, Franz; Heller, Stefan; Berghahn, R�diger
Artificial light is gaining attention as a potential stressor to aquatic ecosystems. Artificial lights located near streams increase light levels experienced by stream invertebrates and we hypothesized light would depress night drift rates. We also hypothesized that the effect of light on drift rates would decrease over time as the invertebrates acclimated to the new light level over the course of one month's exposure. These hypotheses were tested by placing Gammarus spp. in eight, 75 m � 1 m artificial flumes. One flume was exposed to strong (416 lx) artificial light at night. This strong light created a gradient between 4.19 and 0.04 lx over the neighboring six artificial flumes, while a control flume was completely covered with black plastic at night. Night-time light measurements taken in the Berlin area confirm that half the flumes were at light levels experienced by urban aquatic invertebrates. Surprisingly, no light treatment affected gammarid drift rates. In contrast, physical activity measurements of in situ individually caged G. roeseli showed they increased short-term activity levels in nights of complete darkness and decreased activity levels in brightly lit flumes. Both nocturnal and diurnal drift increased, and day drift rates were unexpectadly higher than nocturnal drift. PMID:24688857
Lighting Class Activity: Web Search
NSDL National Science Digital Library
Wolf, Arlynne
This class exercise asks students to use the web to search for lighting resources. Students are asked to find resources that focus on both traditional and green lighting technologies. They will then write a one page report on what they found and the best features of their favorite sites. This assignment would be most useful in a high school or lower college level residential design course. This document may be downloaded in Microsoft Word Doc file format.
Analytic first derivatives of floating occupation molecular orbital-complete active space configuration interaction on graphical processing units.
Hohenstein, Edward G; Bouduban, Marine E F; Song, Chenchen; Luehr, Nathan; Ufimtsev, Ivan S; Mart�nez, Todd J
The floating occupation molecular orbital-complete active space configuration interaction (FOMO-CASCI) method is a promising alternative to the state-averaged complete active space self-consistent field (SA-CASSCF) method. We have formulated the analytic first derivative of FOMO-CASCI in a manner that is well-suited for a highly efficient implementation using graphical processing units (GPUs). Using this implementation, we demonstrate that FOMO-CASCI gradients are of similar computational expense to configuration interaction singles (CIS) or time-dependent density functional theory (TDDFT). In contrast to CIS and TDDFT, FOMO-CASCI can describe multireference character of the electronic wavefunction. We show that FOMO-CASCI compares very favorably to SA-CASSCF in its ability to describe molecular geometries and potential energy surfaces around minimum energy conical intersections. Finally, we apply FOMO-CASCI to the excited state hydrogen transfer reaction in methyl salicylate. PMID:26156469
NSDL National Science Digital Library
Float a ping-pong ball with a hairdryer, as a demonstration of Bernoulli's principle. This classic physics activity includes a twist with the addition of a toilet paper tube that allows learners to explore air pressure in a different way.
Advanced Light Source Activity Report 2000
Greiner, A.; Moxon, L.; Robinson, A.; Tamura, L.
This is an annual report, detailing activities at the Advanced Light Source for the year 2000. It includes highlights of scientific research by users of the facility as well as information about the development of the facility itself.
Green laser light activates the inner ear
Gentiana I. Wenzel; Sven Balster; Kaiyin Zhang; Hubert H. Lim; Uta Reich; Ole Massow; Holger Lubatschowski; Wolfgang Ertmer; Thomas Lenarz; Guenter Reuter
The hearing performance with conventional hearing aids and cochlear implants is dramatically reduced in noisy environments and for sounds more complex than speech (e. g. music), partially due to the lack of localized sensorineural activation across different frequency regions with these devices. Laser light can be focused in a controlled manner and may provide more localized activation of the inner
Mechanics of light-activated network polymers
Kevin Nicholas Long
Mechanically responsive, environmentally activated polymers can undergo large, complex deformation in response to external stimuli such as thermal, luminous, and chemical changes to the environment. Light as a stimulus provides unique application potential because it allows for remote, rapid, and isothermal activation of the material with precise spatial control via existing optical technologies. While certain systems have received considerable attention,
The Northern Lights: Aurora Activity and Latitude
NSDL National Science Digital Library
Sten Odenwald
This activity allows students to make and use a geographic plot of aurora location and activity to create their own forecasting relationship for a selected longitude in North America. They will discover that there is a relationship between the appearance of the aurora and the amount of disturbance to Earth's magnetic field and as the magnetic field becomes more disturbed, the Northern Lights will be visible further south from the Arctic region. By measuring these disturbances, they can predict what the latitude of the southern edge of the Northern Lights will be.
Mechanics of light-activated network polymers
NASA Astrophysics Data System (ADS)
Long, Kevin Nicholas
Mechanically responsive, environmentally activated polymers can undergo large, complex deformation in response to external stimuli such as thermal, luminous, and chemical changes to the environment. Light as a stimulus provides unique application potential because it allows for remote, rapid, and isothermal activation of the material with precise spatial control via existing optical technologies. While certain systems have received considerable attention, the state of the art of most light-activated polymers is limited to basic characterization and demonstrations. To make such materials available to the engineering and scientific communities, physically based theoretical and computational tools are required to guide experimental and design efforts that capitalize on their complex photo-mechanical couplings. The central objective of this thesis is to develop a multi-physics constitutive modeling framework to simulate the continuum scale, photo mechanical behavior of light-activated polymers and implement it into a finite element analysis setting. This framework is independent of specific underlying photo-stimulation mechanisms and is discussed in the context of photo-activated shape memory polymers and network rearranging polymers. Next, the framework is applied to the light-activated network rearranging polymer system, which is relaxed of stress upon irradiation with UV light, and a suite of characterization and application oriented experiments are carried out to calibrate and validate the model's predictive capabilities. The calibrated model is used to investigate several applications such as photo-activated stress relaxation of notched specimens, bending actuation, creep, the buckling of equi-biaxially deformed and irradiated films, and photomechanically formed 1D channels and ridges. Modeling creep involves additional complexity through simultaneous deformation and irradiation, and so the model framework is extended to cover such scenarios. Experiments, finite element analyses, and analytic solutions are developed to explore the phase space available to the experimentalist and design engineer for these different problems.
Green laser light activates the inner ear.
Wenzel, Gentiana I; Balster, Sven; Zhang, Kaiyin; Lim, Hubert H; Reich, Uta; Massow, Ole; Lubatschowski, Holger; Ertmer, Wolfgang; Lenarz, Thomas; Reuter, Guenter
The hearing performance with conventional hearing aids and cochlear implants is dramatically reduced in noisy environments and for sounds more complex than speech (e. g. music), partially due to the lack of localized sensorineural activation across different frequency regions with these devices. Laser light can be focused in a controlled manner and may provide more localized activation of the inner ear, the cochlea. We sought to assess whether visible light with parameters that could induce an optoacoustic effect (532 nm, 10-ns pulses) would activate the cochlea. Auditory brainstem responses (ABRs) were recorded preoperatively in anesthetized guinea pigs to confirm normal hearing. After opening the bulla, a 50-microm core-diameter optical fiber was positioned in the round window niche and directed toward the basilar membrane. Optically induced ABRs (OABRs), similar in shape to those of acoustic stimulation, were elicited with single pulses. The OABR peaks increased with energy level (0.6 to 23 microJ/pulse) and remained consistent even after 30 minutes of continuous stimulation at 13 microJ, indicating minimal or no stimulation-induced damage within the cochlea. Our findings demonstrate that visible light can effectively and reliably activate the cochlea without any apparent damage. Further studies are in progress to investigate the frequency-specific nature and mechanism of green light cochlear activation. PMID:19725719
Study on a Mechanical Semi-Active Heave Compensation System of Drill String for Use on Floating Drilling Platform
Liu, Qingyou; Tang, Yang; Huang, Chongjun; Xie, Chong
There are some disadvantages for existing heave compensation systems of drill string used for the Floating Drilling Platform (FDP), including high energy consumption, large and complex structure, and expensive manufacturing and maintenance costs. In view of the above, we present a streamlined mechanical semi-active heave compensation system (MSAHC) in this study. This system consists of active compensation part with the pinion and rack and passive compensation part. In order to evaluate system performance of the MSAHC, we establish its simulation model with AMEsim software. In the process of simulation, displacement of rotary hook and energy consumption is regarded as performance parameters of the system. And the change rule of two performance parameters are analyzed by changing these design parameters including gear radius of the pinion and rack, scale coefficient of PID, rotary hook load, heave height and heave period of the FDP, and accumulator volume. Then, based on the simulation results of the MSAHC system performance, we have selected out a best set of design parameters from them. Moreover, the feasibility of the design scheme of the MSAHC is effectively verified by comparison with the existing three heave compensation system. The result shows that the energy consumption of the MSAHC is lower than the active heave compensation system (AHC) and the semi-active heave compensation system (SAHC) when achieving a same compensation effect as well as the accumulator volume of MSAHC is half of the passive heave compensation system (PHC). Therefore, the new designed MSAHC not only ensure compensation effect but also lower energy consumption, and its structure is simplified by adopting the simple mechanical structure to decrease manufacturing cost, maintenance cost and floor space. PMID:26186620
Mitochondrial electron transport protects floating leaves of long leaf pondweed (Potamogeton nodosus Poir) against photoinhibition: comparison with submerged leaves.
Shabnam, Nisha; Sharmila, P; Sharma, Anuradha; Strasser, Reto J; Govindjee; Pardha-Saradhi, P
Investigations were carried to unravel mechanism(s) for higher tolerance of floating over submerged leaves of long leaf pondweed (Potamogeton nodosus Poir) against photoinhibition. Chloroplasts from floating leaves showed�~5- and�~6.4-fold higher Photosystem (PS) I (reduced dichlorophenol-indophenol�?�methyl viologen�?�O2) and PS II (H2O�?�parabenzoquine) activities over those from submerged leaves. The saturating rate (V max) of PS II activity of chloroplasts from floating and submerged leaves reached at�~600 and�~230��mol�photons�m(-2)�s(-1), respectively. Photosynthetic electron transport rate in floating leaves was over 5-fold higher than in submerged leaves. Further, floating leaves, as compared to submerged leaves, showed higher F v/F m (variable to maximum chlorophyll fluorescence, a reflection of PS II efficiency), as well as a higher potential to withstand photoinhibitory damage by high light (1,200��mol�photons�m(-2)�s(-1)). Cells of floating leaves had not only higher mitochondria to chloroplast ratio, but also showed many mitochondria in close vicinity of chloroplasts. Electron transport (NADH�?�O2; succinate�?�O2) in isolated mitochondria of floating leaves was sensitive to both cyanide (CN(-)) and salicylhydroxamic acid (SHAM), whereas those in submerged leaves were sensitive to CN(-), but virtually insensitive to SHAM, revealing the presence of alternative oxidase in mitochondria of floating, but not of submerged, leaves. Further, the potential of floating leaves to withstand photoinhibitory damage was significantly reduced in the presence of CN(-) and SHAM, individually and in combination. Our experimental results establish that floating leaves possess better photosynthetic efficiency and capacity to withstand photoinhibition compared to submerged leaves; and mitochondria play a pivotal role in protecting photosynthetic machinery of floating leaves against photoinhibition, most likely by oxidation of NAD(P)H and reduction of O2. PMID:25366828
Photomechanics of light-activated polymers
NASA Astrophysics Data System (ADS)
Long, Kevin N.; Scott, Timothy F.; Jerry Qi, H.; Bowman, Christopher N.; Dunn, Martin L.
Light-activated polymers are an exciting class of modern materials that respond mechanically when irradiated by light at particular wavelengths. While details of the mechanisms that connect the optical excitation to mechanical behavior are complex and differ from material to material, there is sufficient commonality among them to permit the development of a generalized modeling framework to describe the photomechanics. The features shared by light-activated polymers involve light interacting with the material, which triggers photochemical reactions that alter the structure of the crosslinked polymer network. Many such structural alterations result in an evolution of the polymer network, and subsequent macroscopic deformation. When this process is appropriately executed it can enable a photomechanical shape-memory effect. In this paper, we develop a three-dimensional finite-deformation modeling framework to describe the photomechanical response of light-activated polymer systems. This framework integrates four coupled phenomena that contribute to macroscopic photomechanical behavior: photophysics, photochemistry, chemomechanical coupling, and mechanical deformation. The chemomechanical coupling consists of chemically induced structural alterations of the crosslinked network that result in subsequent deformation. We describe this behavior through a decomposition of the crosslinked network into two components consisting of an original network and a photochemically altered network; both evolve during photomechanical deformation. The modeling framework presented in this paper is sufficiently general that it is applicable to light-activated polymer systems that operate with various mechanisms in each of the four areas. Using this modeling approach, we develop constitutive models for two recently developed light-activated polymer systems [Lendlein, A., Hongyan, J., Junger, O., Langer, R., 2005. Light-induced shape-memory polymers. Nature 434 (7035) 879; Scott, T.F., Schneider, A.D., Cook, W.D., Bowman, C.N., 2005. Photoinduced plasticity in crosslinked polymers. Science 308 (5728) 1615]. For the material developed by Scott and his co-workers we validate our model by measuring and numerically simulating photo-induced stress relaxation and bending deformation and obtain good agreement between measurements and predictions. Finally, we use the model to study the effects of photomechanical parameters (applied strain magnitude, irradiation time and intensity, and photoabsorber concentration) and the behavior of the network evolution rule on the material response.
A floating portable pump is constructed of a float defining a well for containing water, a centrifugal pump supported on the float with its impeller shaft extending vertically and with its suction inlet submerged in water in the well, and an internal combustion engine arranged to drive the pump impeller. The pump and engine are secured together on the float
Light Activated Self-Propelled Colloids
J. Palacci; S. Sacanna; S. -H. Kim; G. -R. Yi; D. J. Pine; P. M. Chaikin
Light-activated self-propelled colloids are synthesized and their active motion is studied using optical microscopy. We propose a versatile route using different photoactive materials, and demonstrate a multiwavelength activation and propulsion. Thanks to the photoelectrochemical properties of two semiconductor materials (\\alpha Fe2 O3 and TiO2 ), a light with an energy higher than the bandgap triggers the reaction of decomposition of hydrogen peroxide and produces a chemical cloud around the particle. It induces a phoretic attraction with neighbouring colloids as well as an osmotic self- propulsion of the particle on the substrate. We use these mechanisms to form colloidal cargos as well as self-propelled particles where the light-activated component is embedded into a dielectric sphere. The particles are self-propelled along a direction otherwise randomized by thermal fluctuations, and exhibit a persistent random walk. For sufficient surface density, the particles spontaneously form "living crystals" which are mobile, break apart and reform. Steering the particle with an external magnetic field, we show that the formation of the dense phase results from the collisions heads-on of the particles. This effect is intrinsically non-equilibrium and a novel principle of organization for systems without detailed balance. Engineering families of particles self-propelled by different wavelength demonstrate a good understanding of both the physics and the chemistry behind the system and points to a general route for designing new families of self-propelled particles.
Light-Dependent Electrogenic Activity of Cyanobacteria
Baskakov, Ilia V.
Background Cyanobacteria account for 20�30% of Earth's primary photosynthetic productivity and convert solar energy into biomass-stored chemical energy at the rate of ?450 TW [1]. These single-cell microorganisms are resilient predecessors of all higher oxygenic phototrophs and can be found in self-sustaining, nitrogen-fixing communities the world over, from Antarctic glaciers to the Sahara desert [2]. Methodology/Principal Findings Here we show that diverse genera of cyanobacteria including biofilm-forming and pelagic strains have a conserved light-dependent electrogenic activity, i.e. the ability to transfer electrons to their surroundings in response to illumination. Naturally-growing biofilm-forming photosynthetic consortia also displayed light-dependent electrogenic activity, demonstrating that this phenomenon is not limited to individual cultures. Treatment with site-specific inhibitors revealed the electrons originate at the photosynthetic electron transfer chain (P-ETC). Moreover, electrogenic activity was observed upon illumination only with blue or red but not green light confirming that P-ETC is the source of electrons. The yield of electrons harvested by extracellular electron acceptor to photons available for photosynthesis ranged from 0.05% to 0.3%, although the efficiency of electron harvesting likely varies depending on terminal electron acceptor. Conclusions/Significance The current study illustrates that cyanobacterial electrogenic activity is an important microbiological conduit of solar energy into the biosphere. The mechanism responsible for electrogenic activity in cyanobacteria appears to be fundamentally different from the one exploited in previously discovered electrogenic bacteria, such as Geobacter, where electrons are derived from oxidation of organic compounds and transported via a respiratory electron transfer chain (R-ETC) [3], [4]. The electrogenic pathway of cyanobacteria might be exploited to develop light-sensitive devices or future technologies that convert solar energy into limited amounts of electricity in a self-sustainable, CO2-free manner. PMID:20520829
Neuropharmacology of light-induced locomotor activation.
Amato, Davide; Pum, Martin E; Groos, Dominik; Lauber, Andrea C; Huston, Joseph P; Carey, Robert J; de Souza Silva, Maria A; M�ller, Christian P
Presentation of non-aversive light stimuli for several seconds was found to reliably induce locomotor activation and exploratory-like activity. Light-induced locomotor activity (LIA) can be considered a convenient simple model to study sensory-motor activation. LIA was previously shown to coincide with serotonergic and dopaminergic activation in specific cortical areas in freely moving and anesthetized animals. In the present study we explore the neuropharmacology of LIA using a receptor antagonist/agonist approach in rats. The non-selective 5-HT2-receptor antagonist ritanserin (1.5-6�mg/kg, i.p.) dose-dependently reduced LIA. Selective antagonism of either the 5-HT2A-receptor by MDL 11,939 (0.1-0.4�mg/kg, i.p.), or the 5-HT2C-receptor by SDZ SER 082 (0.125-0.5�mg/kg, i.p.), alone or in combination, had no significant influence on LIA. Also the selective 5-HT1A-receptor antagonist, WAY 100635 (0.4�mg/kg, i.p.) did not affect LIA. Neither did the preferential dopamine D2-receptor antagonist, haloperidol (0.025-0.1�mg/kg, i.p.) nor the D2/D3-receptor agonist, quinpirole (0.025-0.5�mg/kg, i.p.) affect the expression of LIA. However, blocking the glutamatergic NMDA-receptor with phencyclidine (PCP, 1.5-6�mg/kg, i.p.) dose-dependently reduced LIA. This effect was also observed with ketamine (10�mg/kg, i.p.). These findings suggest that serotonin and dopamine receptors abundantly expressed in the cortex do not mediate light-stimulus triggered locomotor activity. PCP and ketamine effects, however, suggest an important role of NMDA receptors in LIA. PMID:25842246
Ultra Low-Voltage\\/Low-Power Digital Floating-Gate Circuits
Y. Berg; D. t. Wisland; T. s. Lande
This paper describes a novel technique for implementing ultra low-voltage\\/low-power digital circuits. The effective threshold voltage seen from a control gate is adjusted during a UV-light activated tuning procedure. The optimal effective threshold voltage matching the supply voltage and speed may be programmed by UV-light through an activated conductance between the power-rails and the floating gates. Measured results are provided
Flinking: Neither Floating nor Sinking.
ERIC Educational Resources Information Center
Wilson, Roger B.
Describes an activity that challenges students to make an object that, when released under water, does not float up or sink down. The main concept this activity investigates is the density of ordinary objects in comparison to the density of water. (PR)
Addressable Floating Light Activated Micro-Electrical Stimulators for Wireless Neurostimulation
Member, IEEE Abstract-- Stimulation of the central nervous system can be useful for treating neurological. INTRODUCTION Electrical stimulation of the central nervous system (CNS) has been used as a treatment larger than 2mm. These RF stimulators are attractive for use in the peripheral nervous system
Whatever Floats Your Boat: A Design Challenge
ERIC Educational Resources Information Center
Kornoelje, Joanne; Roman, Harry T.
This article presents a simple design challenge, based on the PBS program "Design Squad's" "Watercraft" activity that will prove engaging to most technology and engineering students. In this floating boat challenge, students are to build a boat that can float and support 25 pennies for at least 10 seconds--without leaking, sinking, or tipping�
Exploring Floating Concrete and Beam Design.
ERIC Educational Resources Information Center
Snell, Billie G.; Snell, Luke M.
Presents two construction activities that address both state and federal science standards and encourage students to consider career options in mathematics and science. Includes floating concrete and paper bridge activities. (YDS)
Floating sample-collection platform with stage-activated automatic water sampler for streams with large variation in stage
Tarte, Stephen R.; Schmidt, A.R.; Sullivan, Daniel J.
A floating sample-collection platform is described for stream sites where the vertical or horizontal distance between the stream-sampling point and a safe location for the sampler exceed the suction head of the sampler. The platform allows continuous water sampling over the entire storm-runoff hydrogrpah. The platform was developed for a site in southern Illinois.
NSDL National Science Digital Library
Jeff Major
Student preconceptions are one of the greatest challenges we face as science teachers. This Predict, Explain, Observe, and Explain (PEOE) activity challenges students? preconceived notions about why matter floats or sinks when placed in a liquid. The idea behind this model is to do a demonstration that first confirms student's conceptions followed by a second, similar demonstration that provides discrepant information creating cognitive dissonance. Learning happens as students are forced to modify their conceptions so that their view of how things work is not in conflict with what they are seeing.
NSDL National Science Digital Library
This is a hands-on lab activity about seawater density, specifically the relationship between density of fluid, weight of an object, and buoyancy. Learners will develop hypotheses and observe a demonstration of density to understand its role in buoyancy. They will also examine the effect of salinity on density. Background information, common preconceptions, a glossary and more is included. This activity is part of the Aquarius Hands-on Laboratory Activities.
NSDL National Science Digital Library
Mid-continent Research for Education and Learning (McREL)
How can a potato wedge be made to hover in the center of a glass of liquid? This material is part of a series of hands-on science activities designed to arouse student interest. Here students investigate density using potato wedges and water and sugar water solutions. The activity includes a description, a list of science process skills and complex reasoning strategies being used, and a compilation of applicable national science standards for grades K-12. Also provided are content topics, a list of necessary supplies, instructions to perform the activity, and presentation techniques. The activity's content is explained, and assessment suggestions are provided.
NSDL National Science Digital Library
In this chemistry activity, learners observe a combustion reaction and deduce the components necessary for the reaction to occur. They will also see the relationship between pressure, volume, and number of molecules for gasses. This activity, which can also be conducted as a demonstration, illustrates Charles's Law and Boyle's Law.
Lighting and Electrical Plan Class Activity
NSDL National Science Digital Library
Wolf, Arlynne
This class exercise asks students to complete a lighting and electrical plan for a building in the most energy efficient approach possible. They will be given a floor plan to work with, and will then determine which outlets, types of lighting and switches to use. This document may be downloaded in Microsoft Word Doc file format.
NASA Technical Reports Server (NTRS)
Naumann, R. J.
A summary of the Analytical Float Zone Experiment System (AFZES) concept is presented. The types of experiments considered for such a facility are discussed. Reports from various industrial producers and users of float zone material are presented. Special emphasis is placed on state-of-the-art developments in low gravity manufacturing and their applications to space processing.
Moore, Paul A.
be beneficial. Vehicle Selection and Getting To and From The Parade Floats can be built on a variety of beds, dangerous objects, and protruding nails. Many floats will require that you build a frame over the existing wagon. Other designs simply use the wagon bed as is and add the superstructure needed for your design
Advanced Light Source Activity Report 2002
Duque, Theresa; Greiner, Annette; Moxon, Elizabeth; Robinson, Arthur; Tamura, Lori (Editors)
This annual report of the Advanced Light Source details science highlights and facility improvements during the year. It also offers information on events sponsored by the facility, technical specifications, and staff and publication information.
Measurement of action spectra of light-activated processes
NASA Astrophysics Data System (ADS)
Ross, Justin; Zvyagin, Andrei V.; Heckenberg, Norman R.; Upcroft, Jacqui; Upcroft, Peter; Rubinsztein-Dunlop, Halina H.
We report on a new experimental technique suitable for measurement of light-activated processes, such as fluorophore transport. The usefulness of this technique is derived from its capacity to decouple the imaging and activation processes, allowing fluorescent imaging of fluorophore transport at a convenient activation wavelength. We demonstrate the efficiency of this new technique in determination of the action spectrum of the light mediated transport of rhodamine 123 into the parasitic protozoan Giardia duodenalis.
Control of cage lighting by locomotor activity through feedback circuits.
Ferraro, J S; Stone, W; McCormack, C E
This paper describes an electronic device through which environmental lighting conditions are linked to locomotor activity thus allowing only the photosensitive portions of a nocturnal rodents phase-response-curve to be exposed to light. In the past, this type of lighting schedule has been difficult, if not impossible, to present with an exogenously controlled lighting system due to the phase shifting ability of the rodent's circadian system. The feedback lighting system is made from components which can be purchased at most electronics outlets for less than $100. PMID:6514836
Application of floating silicon-based linear multielectrode arrays for acute recording of single neuron activity in awake behaving monkeys.
Bonini, Luca; Maranesi, Monica; Livi, Alessandro; Bruni, Stefania; Fogassi, Leonardo; Holzhammer, Tobias; Paul, Oliver; Ruther, Patrick
One of the fundamental challenges in behavioral neurophysiology in awake animals is the steady recording of action potentials of many single neurons for as long as possible. Here, we present single neuron data obtained during acute recordings mainly from premotor cortices of three macaque monkeys using a silicon-based linear multielectrode array. The most important aspect of these probes, compared with similar models commercially available, is that, once inserted into the brain using a dedicated insertion device providing an intermediate probe fixation by means of vacuum, they can be released and left floating in the brain. On the basis of our data, these features appear to provide (i) optimal physiological conditions for extracellular recordings, (ii) good or even excellent signal-to-noise ratio depending on the recorded brain area and cortical layer, and (iii) extreme stability of the signal over relatively long periods. The quality of the recorded signal did not change significantly after several penetrations into the same restricted cortical sector, suggesting limited tissue damage due to probe insertion. These results indicate that these probes offer several advantages for acute neurophysiological experiments in awake monkeys, and suggest the possibility to employ them for semichronic or even chronic studies. PMID:24434299
bioLights: Light emitting wear for visualizing lower-limb muscle activity
Naoto Igarashi; Kenji Suzuki; Hiroaki Kawamoto; Yoshiyuki Sankai
Analysis of muscle activity by electrophysiological techniques is commonly used to analyze biomechanics. Although the simultaneous and intuitive understanding of both muscle activity and body motion is important in various fields, it is difficult to realize. This paper proposes a novel technique for visualizing physiological signals related to muscle activity by means of surface electromyography. We developed a wearable light-emitting
Point-Light Biological Motion Perception Activates Human Premotor Cortex
Ayse Pinar Saygin; Stephen M. Wilson; Donald J. Hagler Jr; Elizabeth Bates; Martin I. Sereno
Motion cues can be surprisingly powerful in defining objects and events. Specifically, a handful of point-lights attached to the joints of a human actor will evoke a vivid percept of action when the body is in motion. The perception of point-light biological motion activates posterior cortical areas of the brain. On the other hand, observation of others' actions is known
Automatic Iris Segmentation Using Active Near Infra Red Lighting
Carlos Hitoshi Morimoto; Thiago T. Santos; Adriano S. Muniz
This paper introduces a fast, robust and accurate iris segmentation technique based on active lighting. The geom- etry of the light sources, a single camera and the eye facil- itates the detection of the pupil and the automatic selection of the most appropriate image for biometric identification from the video stream, minimizing the effects of noise, dis- tortion and occlusion
Active dielectric antenna on chip for spatial light modulation
Mellor-Crummey, John
to directly interact with and manipulate free-space waves. Using a silicon-based photonic crystal cavity whoseActive dielectric antenna on chip for spatial light modulation Ciyuan Qiu, Jianbo Chen, Yang Xia. Integrated photonic resonators are widely used to manipulate light propagation in an evanescently
Micromechanisms with floating pivot
Garcia, Ernest J. (Albuquerque, NM)
A new class of tilting micromechanical mechanisms have been developed. These new mechanisms use floating pivot structures to relieve some of the problems encountered in the use of solid flexible pivots.
R. Delbourgo
The stable floating configuration of a long plank of rectangular cross section depends on the relative density of the plank to the fluid and on the ratio of the sides. The complete solution of this metacentric problem is given.
Concrete production floating platforms
Letourneur, O.; Falcimaigne, J.
The floating production platforms operating in the North Sea are adapted from drilling semisubmersibles which allow only a limited payload capacity. Experience of concrete production platforms constructed for the North Sea has led Sea Tank Co. to propose a floating platform which offers large payload and oil storage capacities similar to those of existing fixed platforms. Sea Tank Co. and Institut Francais du Petrole joined forces in early 1976 to study the feasibility of a concrete floating production platform incorporating the structure and the production riser together. The results of this 3-yr program show that the concrete floating structure is economically attractive for permanent utilization on a production site. Furthermore, concrete has definite advantages over other materials, in its long term behavior.
Light-activation of teleost rod photoreceptor elongation.
Liepe, B A; Burnside, B
Rod photoreceptors in the retinas of teleost fish undergo changes in cell length in response to changing ambient light intensities. In the dark rods shorten and in the light rods elongate. These movements are mediated by actin-dependent processes which occur in the ellipsoid and myoid of the inner segment. As an approach to examining the underlying intracellular signaling pathways that link light absorption to actin-dependent motility in the inner segment, we have investigated the quantitative aspects of the light stimulus required to activate elongation in isolated rod inner/outer segments (RIS-ROS) of the green sunfish (Lepomis cyanellus). The intensity thresholds and strength-duration characteristics of the light stimulus required to activate teleost rod elongation were found to differ from those reported to activate vertebrate rod membrane hyperpolarization. In response to brief pulses of light, RIS-ROS elongated in a graded manner, both as a function of increasing light pulse intensity and light pulse duration. Half maximal activation of light-induced RIS-ROS elongation was produced by a stimulus of roughly 6 x 10(15) photons cm-2, which is calculated to bleach approximately 20% of the photopigment molecules in green sunfish rod outer segments. This degree of photopigment bleach is approximately 6-7 orders of magnitude greater than that required to elicit half maximal changes in membrane potential in other vertebrate rod preparations. Furthermore, the reciprocal relationship between light pulse intensity and duration in eliciting an equal elongation response held for relatively long light pulse durations.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8405167
NSDL National Science Digital Library
Floating Squares: this is a resource in the collection "General Chemistry Multimedia Problems". In this problem we will coat a piece of notecard with graphite (from pencil lead). We then will float the piece in two beakers containing water and a second solvent. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.
National Synchrotron Light Source 2008 Activity Report
Funded by the U.S. Department of Energy's Office of Basic Energy Sciences, the National Synchrotron Light Source (NSLS) is a national user facility that operates two electron storage rings: X-Ray (2.8 GeV, 300 mA) and Vacuum Ultraviolet (VUV) (800 mev, 1.0A). These two rings provide intense light spanning the electromagnetic spectrum -- from very long infrared rays to ultraviolet light and super-short x-rays -- to analyze very small or highly dilute samples. The properties of this light, and the specially designed experimental stations, called beamlines, allow scientists in many diverse disciplines of research to perform experiments not possible at their own laboratories. Each year, about 2,200 scientists from more than 400 universities and companies use the NSLS for research in such diverse fields as biology, physics, chemistry, geology, medicine, and environmental and materials sciences. For example, researchers have used the NSLS to examine the minute details of computer chips, decipher the structures of viruses, probe the density of bone, determine the chemical composition of moon rocks, and reveal countless other mysteries of science. The facility has 65 operating beamlines, with 51 beamlines on the X-Ray Ring and 14 beamlines on the VUV-Infrared Ring. It runs seven days a week, 24 hours a day throughout the year, except during periods of maintenance and studies. Researchers are not charged for beam time, provided that the research results are published in open literature. Proprietary research is conducted on a full-cost-recovery basis. With close to 1,000 publications per year, the NSLS is one of the most prolific scientific facilities in the world. Among the many accolades given to its users and staff, the NSLS has won nine R&D 100 Awards for innovations ranging from a closed orbit feedback system to the first device able to focus a large spread of high-energy x-rays. In addition, a visiting NSLS researcher shared the 2003 Nobel Prize in Chemistry for work explaining how one class of proteins helps to generate nerve impulses.
NASA Technical Reports Server (NTRS)
Viterna, Larry A. (Inventor)
A floating wind turbine system with a tower structure that includes at least one stability arm extending therefrom and that is anchored to the sea floor with a rotatable position retention device that facilitates deep water installations. Variable buoyancy for the wind turbine system is provided by buoyancy chambers that are integral to the tower itself as well as the stability arm. Pumps are included for adjusting the buoyancy as an aid in system transport, installation, repair and removal. The wind turbine rotor is located downwind of the tower structure to allow the wind turbine to follow the wind direction without an active yaw drive system. The support tower and stability arm structure is designed to balance tension in the tether with buoyancy, gravity and wind forces in such a way that the top of the support tower leans downwind, providing a large clearance between the support tower and the rotor blade tips. This large clearance facilitates the use of articulated rotor hubs to reduced damaging structural dynamic loads. Major components of the turbine can be assembled at the shore and transported to an offshore installation site.
Light onset stimulates tyrosine hydroxylase activity in isolated teleost retinas.
Dearry, A
The action of tyrosine hydroxylase is the rate-limiting step in the synthesis of dopamine, the most abundant catecholamine in vertebrate retinas. I have examined the activation and regulation of this enzyme in isolated retinas of green sunfish, Lepomis cyanellus. Exposing previously dark-adapted retinas to constant illumination for a period of 10 min increased enzymatic activity 2.2-fold over that present in retinas incubated in darkness. Thus, light onset activates tyrosine hydroxylase in teleost retinas. Stimulation of the activity of tyrosine hydroxylase under these conditions was associated with a decrease in the apparent Km of the enzyme for its pteridine cofactor without a change in the apparent Vmax of the reaction. This result suggests that short-term exposure to light increases dopamine synthesis by enhancing the affinity of the enzyme for its naturally occurring cofactor. These findings are consistent with the idea that light activates dopaminergic neurons in teleost retinas. PMID:1688216
Blue Light Stimulates Cognitive Brain Activity in Visually Blind Individuals
Vandewalle, Gilles; Collignon, Olivier; Hull, Joseph T.; Daneault, V�ronique; Albouy, Genevi�ve; Lepore, Franco; Phillips, Christophe; Doyon, Julien; Czeisler, Charles A.; Dumont, Marie; Lockley, Steven W.; Carrier, Julie
Light regulates multiple non-image-forming (or non-visual) circadian, neuroendocrine and neurobehavioral functions, via outputs from intrinsically-photosensitive retinal ganglion cells (ipRGCs). Exposure to light directly enhances alertness and performance, so that light is an important regulator of wakefulness and cognition. The roles of rods, cones and ipRGCs in the impact of light on cognitive brain functions remain unclear, however. A small percentage of blind individuals retain non-image-forming photoreception and offer a unique opportunity to investigate light impacts in the absence of conscious vision, presumably through ipRGCs. Here, we show that three such patients were able to choose non-randomly about the presence of light despite their complete lack of sight. Furthermore, 2s of blue light modified EEG activity when administered simultaneously to auditory stimulations. FMRI further showed that, during an auditory working memory task, less than a minute of blue light triggered the recruitment of supplemental prefrontal and thalamic brain regions involved in alertness and cognition regulation, as well as key areas of the default mode network. These results, which have to be considered as a proof of concept, show that non-image-forming photoreception triggers some awareness for light and can have a more rapid impact on human cognition than previously understood, if brain processing is actively engaged. Furthermore, light stimulates higher cognitive brain activity, independently of vision, and engages supplemental brain areas to perform an ongoing cognitive process. To our knowledge, our results constitute the first indication that ipRGC signaling may rapidly affect fundamental cerebral organization, so that it could potentially participate to the regulation of numerous aspects of human brain function. PMID:23859643
Elucidating the mechanism of wound contraction: rapid versus sustained myosin ATPase activity in attached-delayed-released compared with free-floating fibroblast-populated collagen lattices.
Paul Ehrlich, H; Sun, Bonnie; Kainth, Koijan S; Kromah, Fatuma
Wound contraction closes open wounds by the generation of contractile forces within granulation tissue. We investigated the mechanism of wound contraction using the in vitro fibroblast-populated collagen lattice (FPCL) contraction model. The contraction of the free-floating (FF)-FPCL is through rapid myosin ATPase activity, while the contraction of the attached-delayed-released (ADR)-FPCL is through sustained myosin ATPase activity. All FPCLs were cast identically and the contraction of FF-FPCLs was recorded daily for 4 days and the contraction of ADR-FPCLs was recorded 1 hour after release on day 4. At day, 4 cell numbers were determined and cells undergoing apoptosis were identified and counted. Differences in sustained and rapid myosin ATPase activity were shown by added inosine triphosphate-induced cell contraction in permeabilized fibroblast monolayer preparations. At 2 days, the FF-FPCLs were mostly contracted, while an ADR-FPCL completed contraction 1 hour after release at day 4. Contracted myofibroblasts, identified by alpha-smooth muscle actin-stained stress fibers, were identified in contracted ADR-FPCL, whereas elongated fibroblasts were identified in contracted FF-FPCLs. Vanadate inhibited both inosine triphosphate-induced cell contraction and ADR-FPCL contraction, but neither inhibited ATP-induced cell contraction or FF-FPCL contraction. Genistein inhibited FF-FPCL contraction, but not ADR-FPCL contraction. Advancing tyrosine phosphorylation in fibroblasts promotes rapid myosin ATPase activity, while advancing tyrosine dephosphorylation in myofibroblasts promotes sustained myosin ATPase. The ADR-FPCL had a reduced cell count and a greater proportion of cells had entered apoptosis compared with FF-FPCL. These experiments show that FF-FPCL contraction is through elongated fibroblasts and rapid myosin ATPase, requiring tyrosine phosphorylation. In contrast, the mechanism for ADR-FPCL contraction is through cell contraction by sustained myosin ATPase, involving tyrosine dephosphorylation. PMID:17014676
A review on visible light active perovskite-based photocatalysts.
Kanhere, Pushkar; Chen, Zhong
Perovskite-based photocatalysts are of significant interest in the field of photocatalysis. To date, several perovskite material systems have been developed and their applications in visible light photocatalysis studied. This article provides a review of the visible light (? > 400 nm) active perovskite-based photocatalyst systems. The materials systems are classified by the B site cations and their crystal structure, optical properties, electronic structure, and photocatalytic performance are reviewed in detail. Titanates, tantalates, niobates, vanadates, and ferrites form important photocatalysts which show promise in visible light-driven photoreactions. Along with simple perovskite (ABO3) structures, development of double/complex perovskites that are active under visible light is also reviewed. Various strategies employed for enhancing the photocatalytic performance have been discussed, emphasizing the specific advantages and challenges offered by perovskite-based photocatalysts. This review provides a broad overview of the perovskite photocatalysts, summarizing the current state of the work and offering useful insights for their future development. PMID:25532834
Laser light condensate: experimental demonstration of light-mode condensation in actively mode locked laser.
Weill, Rafi; Levit, Boris; Bekker, Alexander; Gat, Omri; Fischer, Baruch
We have recently predicted (R. Weill, B. Fischer and O. Gat, Phys. Rev. Lett.104, 173901, 2010) condensation of light in actively mode locked lasers when the laser power increases, or the noise, that takes the role of temperature, decreases. The condensate is characterized by strong light pulses due to the dominance of the lowest eigenmode ("ground state") power. Here, we experimentally demonstrate, for the first time, light mode condensation transition in an actively mode-locked fiber laser. Following the theoretical prediction, the condensation is obtained for modulations that have a power law dependence on time with exponents smaller than 2. The laser light system is strictly one dimensional, a special opportunity in experimental physics. We also discuss experimental schemes for condensation in two- and three-dimensional laser systems. PMID:20721041
Spatial Confinement of Laser Light in Active Random Media
NASA Astrophysics Data System (ADS)
Cao, H.; Xu, J. Y.; Zhang, D. Z.; Chang, S.-H.; Ho, S. T.; Seelig, E. W.; Liu, X.; Chang, R. P. H.
We have observed spatial confinement of laser light in micrometer-sized random media. The optical confinement is attributed to the disorder-induced scattering and interference. Our experimental data suggest that coherent amplification of the scattered light enhances the interference effect and helps the spatial confinement. Using the finite-difference time-domain method, we simulate lasing with coherent feedback in the active random medium.
Light-mode condensation in actively-mode-locked lasers.
Weill, Rafi; Fischer, Baruch; Gat, Omri
We show that the formation of pulses in actively mode-locked lasers exhibits in certain conditions a transition of the laser mode system to a light pulse state that is similar to Bose-Einstein condensation (BEC). The study is done in the framework of statistical light-mode dynamics with a mapping between the distribution of the laser eigenmodes to the equilibrium statistical physics of noninteracting bosons in an external potential. The light-mode BEC transition occurs for a mode-locking modulation that has a power law dependence on time with an exponent smaller than 2. PMID:20482109
Light-Mode Condensation in Actively-Mode-Locked Lasers
NASA Astrophysics Data System (ADS)
Weill, Rafi; Fischer, Baruch; Gat, Omri
We show that the formation of pulses in actively mode-locked lasers exhibits in certain conditions a transition of the laser mode system to a light pulse state that is similar to Bose-Einstein condensation (BEC). The study is done in the framework of statistical light-mode dynamics with a mapping between the distribution of the laser eigenmodes to the equilibrium statistical physics of noninteracting bosons in an external potential. The light-mode BEC transition occurs for a mode-locking modulation that has a power law dependence on time with an exponent smaller than 2.
Ecological measurements of light exposure, activity, and circadian disruption.
Miller, D; Bierman, A; Figueiro, Mg; Schernhammer, Es; Rea, Ms
Circadian rhythms are biological rhythms that repeat at approximately 24 hours. In humans, circadian rhythms have an average period of 24.2 hours. The 24-hour patterns of light and dark on the retina synchronize circadian rhythms to the local time on earth. Lighting characteristics affecting circadian rhythms are very different than those affecting visual responses. Lack of synchronization between the endogenous clock and the local time has been associated with a host of maladies. Therefore, it is important to measure circadian light exposures over the course of the 24-hour day and to be able to assess circadian entrainment and disruption in actual living environments. Presented is an overview of the recently developed Daysimeter, a personal measurement device for recording activity and circadian light-exposure. When the Daysimeter is worn on the head, two light sensors near the eye are used to estimate circadian light (CLA) exposures over extended periods of time. Phasor analysis combines the measured periodic activity-rest patterns with the measured periodic light-dark patterns to assess behavioural circadian entrainment/disruption. As shown, day-shift and rotating-shift nurses exhibit remarkably different levels of behavioural circadian entrainment/disruption. These new ecological measurement and analysis techniques may provide important insights into the relationship between circadian disruption and well-being. PMID:23504497
The floating water bridge The floating water bridge
Podgornik, Rudolf
The floating water bridge The floating water bridge Elmar C. Fuchs1 , Jakob Woisetschl�ger2 , Karl ____________________________________________ Abstract When high voltage is applied to distilled water filled into two glass beakers which are in contact, a stable water connection forms spontaneously, giving the impression of a floating water bridge. A detailed
Ultraviolet B light stimulates hornet activities - a review
NASA Astrophysics Data System (ADS)
Ishay, Jacob S.; Kirshboim, Shira
For more than 30 years now, we have been gathering data on vespan activity in the field and laboratory under the influence of various factors. We found that light is most influential on the behaviour and activities of hornets (Hymenoptera, Vespinae); among various light wavelengths, the greatest influence was ascribed to the ultraviolet bandwidth (UVB). Prominent vespan activities outside their nest included digging, that is, the removal of soil from the nest, and we found this activity to take place at high noon, when the UV radiation, especially the UVB fraction, is maximal. In fact the digging activity of hornets was at times fully coordinated with the solar radiation, especially with the UVB portion of it, so that in daytime hours with diminished UV radiation, as in the morning or the afternoon, this activity and also flights outside the nest were accordingly curtailed, whereas at night there was no vespan flight at all. Under laboratory conditions, we found that hornets subjected to ether anaesthesia awaken faster when exposed to UV light than do control hornets left in the dark. In this connection, the exposure of pieces of hornet cuticle to UV light resulted in enhanced light absorption by the cuticle, but the absorption level reverted to normal after a period of rest in the dark. Tests for cuticular fluorescence after its irradiation with UVB light (290 nm) revealed a dominant emission in both UV and visible light. Furthermore, exposure of the cuticle of either live or dead hornets to light results in a photovoltaic effect which amplifies under UV irradiation. The hornet cuticle appears to behave like a semiconductor with traps and under the influence of light irradiation the electrical conductivity diminishes. The cuticle exposed to UV irradiation undergoes polarization, as do ferroelectric substances after being exposed to an electric field. The present paper summarizes the results of experiments and observations carried out on both live and dead hornets, from all of which emerges the conclusion that UV light is a factor which attracts hornets and influences them, while the hornets, in turn, utilize it for their own purposes. The latter utilization is achieved in cooperation with bacterial symbionts such as Staphylococcus xylosus and S. gallinarum.
Can flexibility help you float?
Burton, Lisa Janelle
We consider the role of flexibility in the weight-bearing characteristics of bodies floating at an interface. Specifically, we develop a theoretical model for a two-dimensional thin floating plate that yields the maximum ...
Lightly stuffed pyrochlore structure of single-crystalline Yb2Ti2O7 grown by the optical floating zone technique
NASA Astrophysics Data System (ADS)
Ross, K. A.; Proffen, Th.; Dabkowska, H. A.; Quilliam, J. A.; Yaraskavitch, L. R.; Kycia, J. B.; Gaulin, B. D.
Recent neutron scattering and specific heat studies on the pyrochlore Yb2Ti2O7 have revealed variations in its magnetic behavior below 265 mK. In the best samples, a sharp anomaly in the specific heat is observed at T=265 mK. Other samples, especially single crystals, have broad features in the specific heat which vary in sharpness and temperature depending on the sample, indicating that the magnetic ground state may be qualitatively different in such samples. We performed detailed comparisons of the chemical structure of a pulverized single crystal of Yb2Ti2O7, grown by the floating zone technique, to a sintered powder sample of Yb2Ti2O7. Rietveld refinements of neutron powder diffraction data on these samples reveal that the crushed single crystal is best described as a �stuffed� pyrochlore, Yb2(Ti2-xYbx)O7-x/2 with x = 0.046(4), despite perfectly stoichiometric starting material. Substituting magnetic Yb3+ on the nonmagnetic Ti4+ sublattice would introduce random exchange bonds and local lattice deformations. These are expected to be the mechanism leading to the variation of the delicate magnetic ground state of Yb2Ti2O7. Determination of the cubic cell length a could be useful as a method for characterizing the stoichiometry of nonpulverized single crystals at room temperature.
Resveratrol prevents light-induced retinal degeneration via suppressing activator protein-1 activation.
Kubota, Shunsuke; Kurihara, Toshihide; Ebinuma, Mari; Kubota, Miyuki; Yuki, Kenya; Sasaki, Mariko; Noda, Kousuke; Ozawa, Yoko; Oike, Yuichi; Ishida, Susumu; Tsubota, Kazuo
Light damage to the retina accelerates retinal degeneration in human diseases and rodent models. Recently, the polyphenolic phytoalexin resveratrol has been shown to exert various bioactivities in addition to its classical antioxidant property. In the present study, we investigated the effect of resveratrol on light-induced retinal degeneration together with its underlying molecular mechanisms. BALB/c mice with light exposure (5000-lux white light for 3 hours) were orally pretreated with resveratrol at a dose of 50 mg/kg for 5 days. Retinal damage was evaluated by TdT-mediated dUTP nick-end labeling, outer nuclear layer morphometry, and electroretinography. Administration of resveratrol to mice with light exposure led to a significant suppression of light-induced pathological parameters, including TdT-mediated dUTP nick-end labeling-positive retinal cells, outer nuclear layer thinning, and electroretinography changes. To clarify the underlying molecular mechanisms, the nuclear translocation of activator protein-1 subunit c-fos was evaluated by enzyme-linked immunosorbent assay, and the retinal activity of sirtuin 1 was measured by deacetylase fluorometric assay. Retinal activator protein-1 activation, up-regulated following light exposure, was significantly reduced by application of resveratrol. In parallel, retinal sirtuin 1 activity, reduced in animals with light damage, was significantly augmented by resveratrol treatment. Our data suggest the potential use of resveratrol as a therapeutic agent to prevent retinal degeneration related to light damage. PMID:20709795
Global Positioning System Synchronized Active Light Autonomous Docking System
NASA Technical Reports Server (NTRS)
Howard, Richard (inventor)
A Global Positioning System Synchronized Active Light Autonomous Docking System (GPSSALADS) for automatically docking a chase vehicle with a target vehicle comprises at least one active light emitting target which is operatively attached to the target vehicle. The target includes a three-dimensional array of concomitantly flashing lights which flash at a controlled common frequency. The GPSSALADS further comprises a visual tracking sensor operatively attached to the chase vehicle for detecting and tracking the target vehicle. Its performance is synchronized with the flash frequency of the lights by a synchronization means which is comprised of first and second internal clocks operatively connected to the active light target and visual tracking sensor, respectively, for providing timing control signals thereto, respectively. The synchronization means further includes first and second Global Positioning System receivers operatively connected to the first and second internal clocks, respectively, for repeatedly providing simultaneous synchronization pulses to the internal clocks, respectively. In addition, the GPSSALADS includes a docking process controller means which is operatively attached to the chase vehicle and is responsive to the visual tracking sensor for producing commands for the guidance and propulsion system of the chase vehicle.
Global Positioning System Synchronized Active Light Autonomous Docking System
NASA Technical Reports Server (NTRS)
Howard, Richard T. (Inventor); Book, Michael L. (Inventor); Bryan, Thomas C. (Inventor); Bell, Joseph L. (Inventor)
A Global Positioning System Synchronized Active Light Autonomous Docking System (GPSSALADS) for automatically docking a chase vehicle with a target vehicle comprising at least one active light emitting target which is operatively attached to the target vehicle. The target includes a three-dimensional array of concomitantly flashing lights which flash at a controlled common frequency. The GPSSALADS further comprises a visual tracking sensor operatively attached to the chase vehicle for detecting and tracking the target vehicle. Its performance is synchronized with the flash frequency of the lights by a synchronization means which is comprised of first and second internal clocks operatively connected to the active light target and visual tracking sensor, respectively, for providing timing control signals thereto, respectively. The synchronization means further includes first and second Global Positioning System receivers operatively connected to the first and second internal clocks, respectively, for repeatedly providing simultaneous synchronization pulses to the internal clocks, respectively. In addition, the GPSSALADS includes a docking process controller means which is operatively attached to the chase vehicle and is responsive to the visual tracking sensor for producing commands for the guidance and propulsion system of the chase vehicle.
Compound floating pivot micromechanisms
Garcia, Ernest J. (Albuquerque, NM)
A new class of tilting micromechanical mechanisms have been developed. These new mechanisms use compound floating pivot structures to attain far greater tilt angles than are practical using other micromechanical techniques. The new mechanisms are also capable of bi-directional tilt about multiple axes.
Corona from floating electrodes
Francisco Roman; Vernon Cooray; Viktor Scuka
It is not unusual to have insulated conducting objects located close to the conductors of a Lightning Protection System. However, the separation of these objects from the Lightning Protection System could vary from a few millimetres to some centimetres. When the system is exposed to thunderstorm electric fields, discharge could be initiated between the Lightning Protection System and the floating
Infrared light utilized for photodynamic therapy by activation of rare earth phosphors for visible light generation
NASA Astrophysics Data System (ADS)
Collins, Joshua E.; Lakshman, Thiru V.; Finlay, Jarod E.; Kumar, Ajith; Bell, Howard; Nguyen, Ba T.; Belov, Valery; Luo, Jun; Friedberg, Joseph S.
Introduction: Photodynamic therapy (PDT) is a treatment for cancer requiring activation of a photosensitizer for light-mediated tumor cytotoxicity. PDT is limited by tissue penetration because visible light is required for photosensitizer activation. Sunstones TM are rare-earth phosphors which up-convert energy from infrared wavelengths to emit higher energy in the visible spectrum. We utilized this unique characteristic to generate light of appropriate intensity and wavelength for photosensitizer activation and subsequent tumor cell eradication. Methods: Sunstones TM with infrared absorption at 808 and 980nm and visible two-photon emission at 549.9 and 663.1nm were used. A murine NSCLC line was used to determine in vitro toxicity of Sunstones TM and dose response curves for Sunstones TM-mediated PDT. Human NSCLC cells were incubated with/without Photofrin TM (photosensitizer). Experimental groups included: Infrared light treatment (IR), IR+Photofrin TM, IR+Sunstones TM, and IR+Sunstones TM+Photofrin TM. Groups were exposed to 2.5W of 808nm light and assayed for metabolic activity. Results: In vitro toxicity assays showed no significant toxicological side effects after 1 week incubation with Sunstones TM and demonstrated linear response in cytotoxicity as treatment times and infrared dose increased. IR+Sunstones TM+Photofri TM group showed significantly decreased metabolic activity compared to control cells, cells treated with IR+Sunstones TM, and IR alone. Conclusion: Sunstones TM are nontoxic nanocrystals capable of activating photosensitizers for PDT. Future directions include conjugation of up-converters to a novel photosensitizer and managing the selective uptake of conjugate by tumor cells.
Recording invertebrate nerve activation with modulated light changes
McCluskey, Matthew
. We used the lobster nerve as a model system to investigate and record event-related optical signals. The photon delay was below the detection threshold, in part due to the small size of the nerve bundle. OurRecording invertebrate nerve activation with modulated light changes Matthew D. McCluskey, Jeffrey
Selenium bond decreases ON resistance of light-activated switch
NASA Technical Reports Server (NTRS)
Vitrified amorphous selenium bond decreases the ON resistance of a gallium arsenide-silicon light-activated, low-level switch. The switch is used under a pulse condition to prolong switch life and minimize errors due to heating, devitrification, and overdrawing.
Analysis of an Anomaly: The Increase in Time Float following Consumption
Qi, Jianxun; Su, Zhixiong
One fundamental axiom for project plan and schedule relates to the notion that time float will be reduced following its consumption. However, an anomalous scenario can emerge in which an activity's time float increases following its consumption. By exploring the associations between time float and paths in activity networks, we (a) reveal the conditions under which the anomaly occurs and (b) summarize laws related to total float. An activity's total float increases in parallel with its duration prolongation within a given boundary but remains constant or decreases in parallel with a prolongation outside the boundary. Furthermore, whereas a prolongation of an activity's duration in excess of classic total float does not delay project completion time, a lag of its start time to a degree slightly greater than the total float does. This analysis reveals different types of total float that correspond to different ways of usage. From this, we offer definitions for translation total float and prolongation total float that deviate from traditional conventions regarding the uniqueness of total float. PMID:25250376
Biocidal activity of a light-absorbing fluorescent conjugated polyelectrolyte.
Lu, Liangde; Rininsland, Frauke H; Wittenburg, Shannon K; Achyuthan, Komandoor E; McBranch, Duncan W; Whitten, David G
Herein we describe studies that indicate a cationic conjugated polyelectrolyte shows biocidal activity against gram-negative bacteria (Escherichia coli, E. coli, BL21, with plasmids for Azurin and ampicillin resistance) and gram-positive bacterial spores (Bacillus anthracis, Sterne, B. anthracis, Sterne). These studies were carried out with aqueous suspensions of the conjugated polyelectrolyte, with the polyelectrolyte in supported formats and with samples in which the conjugated polyelectrolyte was coated on the bacteria. The results are interesting in that the biocidal activity is light-induced and appears effective due to the ability of the conjugated polyelectrolyte to form a surface coating on both types of bacteria. The effects observed here should be general and suggest that a range of conjugated polyelectrolytes in different formulations may provide a useful new class of biocides for both dark and light-activated applications. PMID:16229539
Transient and selective suppression of neural activity with infrared light
Duke, Austin R.; Jenkins, Michael W.; Lu, Hui; McManus, Jeffrey M.; Chiel, Hillel J.; Jansen, E. Duco
Analysis and control of neural circuitry requires the ability to selectively activate or inhibit neurons. Previous work showed that infrared laser light selectively excited neural activity in endogenous unmyelinated and myelinated axons. However, inhibition of neuronal firing with infrared light was only observed in limited cases, is not well understood and was not precisely controlled. Using an experimentally tractable unmyelinated preparation for detailed investigation and a myelinated preparation for validation, we report that it is possible to selectively and transiently inhibit electrically-initiated axonal activation, as well as to both block or enhance the propagation of action potentials of specific motor neurons. Thus, in addition to previously shown excitation, we demonstrate an optical method of suppressing components of the nervous system with functional spatiotemporal precision. We believe this technique is well-suited for non-invasive investigations of diverse excitable tissues and may ultimately be applied for treating neurological disorders. PMID:24009039
Light-Activated Proteolysis for the Spatiotemporal Control of Proteins.
Delacour, Quentin; Li, Chenge; Plamont, Marie-Aude; Billon-Denis, Emmanuelle; Aujard, Isabelle; Le Saux, Thomas; Jullien, Ludovic; Gautier, Arnaud
The regulation of proteolysis is an efficient way to control protein function in cells. Here, we present a general strategy enabling to increase the spatiotemporal resolution of conditional proteolysis by using light activation as trigger. Our approach relies on the auxin-inducible degradation system obtained by transposing components of the plant auxin-dependent degradation pathway in mammalian cells. We developed a photoactivatable auxin that acts as a photoactivatable inducer of degradation. Upon local and short light illumination, auxin is released in cells and triggers the degradation of a protein of interest with spatiotemporal control. PMID:25938742
Vitamin A activates rhodopsin and sensitizes it to ultraviolet light
Miyazono, Sadaharu; Isayama, Tomoki; Delori, Fran�ois C.; Makino, Clint L.
The visual pigment, rhodopsin, consists of opsin protein with 11-cis retinal chromophore, covalently bound. Light activates rhodopsin by isomerizing the chromophore to the all-trans conformation. The activated rhodopsin sets in motion a biochemical cascade that evokes an electrical response by the photoreceptor. All-trans retinal is eventually released from the opsin and reduced to vitamin A. Rod and cone photoreceptors contain vast amounts of rhodopsin, so after exposure to bright light, the concentration of vitamin A can reach relatively high levels within their outer segments. Since a retinal analog, ?-ionone, is capable of activating some types of visual pigments, we tested whether vitamin A might produce a similar effect. In single-cell recordings from isolated dark-adapted salamander green-sensitive rods, exogenously applied vitamin A decreased circulating current and flash sensitivity and accelerated flash response kinetics. These changes resembled those produced by exposure of rods to steady light. Microspectrophotometric measurements showed that vitamin A accumulated in the outer segments and binding of vitamin A to rhodopsin was confirmed in in vitro assays. In addition, vitamin A improved the sensitivity of photoreceptors to ultraviolet (UV) light. Apparently, the energy of a UV photon absorbed by vitamin A transferred by a radiationless process to the 11-cis retinal chromophore of rhodopsin, which subsequently isomerized. Therefore, our results suggest that vitamin A binds to rhodopsin at an allosteric binding site distinct from the chromophore binding pocket for 11-cis retinal to activate the rhodopsin, and that it serves as a sensitizing chromophore for UV light. PMID:22192505
Anticipatory active-site motions and chromophore distortion prime photoreceptor PYP for light activation.
Getzoff, Elizabeth D; Gutwin, Karl N; Genick, Ulrich K
Protein photoreceptors use small-molecule cofactors called chromophores to detect light. Only under the influence of the receptors' active sites do these chromophores adopt spectral and photochemical properties that suit the receptors' functional requirements. This protein-induced change in chromophore properties is called photochemical tuning and is a prime example for the general--but poorly understood--process of chemical tuning through which proteins shape the reactivity of their active-site groups. Here we report the 0.82-A resolution X-ray structure of the bacterial light receptor photoactive yellow protein (PYP). The unusually precise structure reveals deviations from expected molecular geometries and anisotropic atomic displacements in the PYP active site. Our analysis of these deviations points directly to the intramolecular forces and active-site dynamics that tune the properties of PYP's chromophore to absorb blue light, suppress fluorescence, and favor the required light-driven double-bond isomerization. PMID:12872160
Serial floating point formatter
Peterson, R. D.; Penner, W. A.
A floating point formatter for changing fixed point serial digital data, such as that received by a seismic data acquisition system, is disclosed wherein fixed point serial digital data is received and scaled to remove any bias added by preamplification. The scaled data is shifted a predetermined number of bits and a resulting exponent is calculated. The shifted data signal and corresponding exponent are combined and further scaled to permit stacking the data without exceeding the system capacity.
Chang Q. Sun
Because of the segmental specific-heat disparity of the hydrogen bond (O:H-O) and the Coulomb repulsion between oxygen ions, cooling elongates the O:H-O bond at freezing by stretching its containing angle and shortening the H-O bond with an association of larger O:H elongation, which makes ice less dense than water, allowing it to float.
Wiring the retinal circuits activated by light during early development
Background Light information is sorted by neuronal circuits to generate image-forming (IF) (interpretation and tracking of visual objects and patterns) and non-image-forming (NIF) tasks. Among the NIF tasks, photic entrainment of circadian rhythms, the pupillary light reflex, and sleep are all associated with physiological responses, mediated mainly by a small group of melanopsin-expressing retinal ganglion cells (mRGCs). Using Xenopus laevis as a model system, and analyzing the c-fos expression induced by light as a surrogate marker of neural activity, we aimed to establish the developmental time at which the cells participating in both systems come on-line in the retina. Results We found that the peripheral retina contains 80% of the two melanopsin-expressing cell types we identified in Xenopus: melanopsin-expressing horizontal cells (mHCs; opn4m+/opn4x+/Prox1+) and mRGCs (2.7% of the total RGCs; opn4m+/opn4x+/Pax6+/Isl1), in a ratio of 6:1. Only mRGCs induced c-fos expression in response to light. Dopaminergic (tyrosine hydroxylase-positive; TH+) amacrine cells (ACs) may be part of the melanopsin-mediated circuit, as shown by preferential c-fos induction by blue light. In the central retina, two cell types in the inner nuclear layer (INL) showed light-mediated induction of c-fos expression [(On-bipolar cells (Otx2+/Isl1+), and a sub-population of ACs (Pax6?/Isl1?)], as well as two RGC sub-populations (Isl1+/Pax6+ and Isl1+/Pax6?). Melanopsin and opsin expression turned on a day before the point at which c-fos expression could first be activated by light (Stage 37/38), in cells of both the classic vision circuit, and those that participate in the retinal component of the NIF circuit. Key to the classic vision circuit is that the component cells engage from the beginning as functional �unit circuits� of two to three cells in the INL for every RGC, with subsequent growth of the vision circuit occurring by the wiring in of more units. Conclusions We identified melanopsin-expressing cells and specific cell types in the INL and the RGC layer which induce c-fos expression in response to light, and we determined the developmental time when they become active. We suggest an initial formulation of retinal circuits corresponding to the classic vision pathway and melanopsin-mediated circuits to which they may contribute. PMID:24521229
WindFloat: A floating foundation for offshore wind turbines
Dominique Roddier; Christian Cermelli; Alexia Aubault; Alla Weinstein
This manuscript summarizes the feasibility study conducted for the WindFloat technology. The WindFloat is a three-legged floating foundation for multimegawatt offshore wind turbines. It is designed to accommodate a wind turbine, 5 MW or larger, on one of the columns of the hull with minimal modifications to the nacelle and rotor. Potential redesign of the tower and of the turbine
DENORMAL NUMBERS IN FLOATING POINT SIGNAL PROCESSING APPLICATIONS Denormal numbers in floating point signal
Mascarenhas, Walter Figueiredo
DENORMAL NUMBERS IN FLOATING POINT SIGNAL PROCESSING APPLICATIONS Denormal numbers in floating Signal Processing, CPU Copyright 2002-2005 � Laurent de Soras Page 1/10 #12;DENORMAL NUMBERS IN FLOATING.............................................................................................................. 2 1. FLOATING POINT NUMBER CODING OVERVIEW...................................................... 3 1
Channelrhodopsins: visual regeneration and neural activation by a light switch
Natasha, G; Tan, Aaron; Farhatnia, Yasmin; Rajadas, Jayakumar; Hamblin, Michael R.; Khaw, Peng T.; Seifalian, Alexander M.
The advent of optogenetics provides a new direction for the field of neuroscience and biotechnology, serving both as a refined investigative tool and as potential cure for many medical conditions via genetic manipulation. Although still in its infancy, recent advances in optogenetics has made it possible to remotely manipulate in vivo cellular functions using light. Coined Nature Methods� �Method of the Year� in 2010, the optogenetic toolbox has the potential to control cell, tissue and even animal behaviour. This optogenetic toolbox consists of light-sensitive proteins that are able to modulate membrane potential in response to light. Channelrhodopsins (ChR) are light-gated microbial ion channels, which were first described in green algae. ChR2 (a subset of ChR) is a seven transmembrane a helix protein, which evokes membrane depolarization and mediates an action potential upon photostimulation with blue (470 nm) light. By contrast to other seven-transmembrane proteins that require second messengers to open ion channels, ChR2 form ion channels themselves, allowing ultrafast depolarization (within 50 milliseconds of illumination). It has been shown that integration of ChR2 into various tissues of mice can activate neural circuits, control heart muscle contractions, and even restore breathing after spinal cord injury. More compellingly, a plethora of evidence has indicated that artificial expression of ChR2 in retinal ganglion cells can reinstate visual perception in mice with retinal degeneration. PMID:23664865
Acceptor impurity activation in III-nitride light emitting diodes
NASA Astrophysics Data System (ADS)
R�mer, Friedhard; Witzigmann, Bernd
In this work, the role of the acceptor doping and the acceptor activation and its impact on the internal quantum efficiency (IQE) of a Gallium Nitride (GaN) based multi-quantum well light emitting diode is studied by microscopic simulation. Acceptor impurities in GaN are subject to a high activation energy which depends on the presence of proximate dopant atoms and the electric field. A combined model for the dopant ionization and activation barrier reduction has been developed and implemented in a semiconductor carrier transport simulator. By model calculations, we demonstrate the impact of the acceptor activation mechanisms on the decay of the IQE at high current densities, which is known as the efficiency droop. A major contributor to the droop is the electron leakage which is largely affected by the acceptor doping.
Float level switch for a nuclear power plant containment vessel
Powell, J.G.
This invention is a float level switch used to sense rise or drop in water level in a containment vessel of a nuclear power plant during a loss of coolant accident. The essential components of the device are a guide tube, a reed switch inside the guide tube, a float containing a magnetic portion that activates a reed switch, and metal-sheathed, ceramic-insulated conductors connecting the reed switch to a monitoring system outside the containment vessel. Special materials and special sealing techniques prevent failure of components and allow the float level switch to be connected to a monitoring system outside the containment vessel. 1 figures.
Float level switch for a nuclear power plant containment vessel
Powell, James G. (Clifton Park, NY)
This invention is a float level switch used to sense rise or drop in water level in a containment vessel of a nuclear power plant during a loss of coolant accident. The essential components of the device are a guide tube, a reed switch inside the guide tube, a float containing a magnetic portion that activates a reed switch, and metal-sheathed, ceramic-insulated conductors connecting the reed switch to a monitoring system outside the containment vessel. Special materials and special sealing techniques prevent failure of components and allow the float level switch to be connected to a monitoring system outside the containment vessel.
Genetics Home Reference: Floating-Harbor syndrome
... PubMed Recent literature OMIM Genetic disorder catalog Conditions > Floating-Harbor syndrome On this page: Description Genetic changes ... names Glossary definitions Reviewed December 2012 What is Floating-Harbor syndrome? Floating-Harbor syndrome is a disorder ...
Effect of temperature and nutrients on the competition between free-floating Salvinia natans and submerged Elodea nuttallii in mesocosms
J. J. C. Netten; G. H. P. Arts; R. Gylstra; Nes van E. H; M. Scheffer; R. M. M. Roijackers
In many aquatic ecosystems, free-floating plants compete with submerged plants for nutrients and light. Being on top of the water surface free-floating plants are superior competitors for light. Submerged plants can take up nutrients from the sediment and the water column, hereby reducing these levels for free-floating plants. Global warming may change chances of successful species invasion and can alter
Glucocorticoid receptor activity regulates light adaptation in the zebrafish retina
Muto, Akira; Taylor, Michael R.; Suzawa, Miyuki; Korenbrot, Juan I.; Baier, Herwig
Glucocorticoids modulate diverse aspects of physiology and behavior, including energy homeostasis, stress response, and memory, through activation of the glucocorticoid receptor (GR). Light perception has profound effects on the production of glucocorticoids via functional connections of the retina to the hypothalamus-pituitary-adrenal axis. We report here that glucocorticoids can also signal in the reverse direction, i. e., regulate visual function in zebrafish, Danio rerio. The zebrafish GR mutant, grs357, harbors a missense mutation that completely blocks the transcriptional activity of GR. In this mutant, visual behavior was abolished following a period of darkness and recovered sluggishly after return to the light. Electrophysiological measurements showed that the photoresponse of the dark-adapted retina was reduced in the mutant and re-adapted to light with a substantial delay. Several gene products, including some that are important for dopaminergic signaling, were misregulated in grs357 mutants. We suggest that GR controls a gene network required for visual adaptation in the zebrafish retina and potentially integrates neuroendocrine and sensory responses to environmental changes. PMID:24068988
Light-induced self-assembly of active rectification devices
J. Stenhammar; R. Wittkowski; D. Marenduzzo; M. E. Cates
Self-propelled colloidal objects, such as motile bacteria or synthetic microswimmers, have microscopically irreversible individual dynamics - a feature they share with all living systems. The incoherent behaviour of individual swimmers can then be harnessed (or "rectified") by microfluidic devices that create systematic motions impossible in equilibrium. Examples include flow of rotor particles round a circuit, steady rotation of a gear wheel in a bacterial bath, and pumping of bacteria between chambers by "funnel gates". Here we present a computational proof-of-concept study, showing that such active rectification devices might be created directly from an unstructured "primordial soup" of motile particles, solely by using spatially modulated illumination to control their local propulsion speed. Alongside both microscopic irreversibility and speed modulation, our mechanism requires spatial symmetry breaking, such as a chevron light pattern, and strong interactions between particles, such as volume exclusion causing a collisional slow-down at high density. These four factors create a many-body rectification mechanism that generically differs from one-body microfluidic antecedents. Our work suggests that standard spatial-light-modulator technology might allow the programmable, light-induced self-assembly of active rectification devices from an unstructured particle bath.
Changes in the colour of light cue circadian activity
Kuchenbecker, James A.; Neitz, Maureen
The discovery of melanopsin, the non-visual opsin present in intrinsically photosensitive retinal ganglion cells (ipRGCs), has created great excitement in the field of circadian biology. Now, researchers have emphasized melanopsin as the main photopigment governing circadian activity in vertebrates. Circadian biologists have tested this idea under standard laboratory, 12h Light: 12h Dark, lighting conditions that lack the dramatic daily colour changes of natural skylight. Here we used a stimulus paradigm in which the colour of the illumination changed throughout the day, thus mimicking natural skylight, but luminance, sensed intrinsically by melanopsin containing ganglion cells, was kept constant. We show in two species of cichlid, Aequidens pulcher and Labeotropheus fuelleborni, that changes in light colour, not intensity, are the primary determinants of natural circadian activity. Moreover, opponent-cone photoreceptor inputs to ipRGCs mediate the sensation of wavelength change, and not the intrinsic photopigment, melanopsin. These results have implications for understanding the evolutionary biology of non-visual photosensory pathways and answer long-standing questions about the nature and distribution of photopigments in organisms, including providing a solution to the mystery of why nocturnal animals routinely have mutations that interrupt the function of their short wavelength sensitive photopigment gene. PMID:22639465
Guillaume Bossard; Stefanos Katmadas
We define a new partially solvable system of equations that parametrises solutions to six-dimensional N=(1,0) ungauged supergravity coupled to tensor multiplets. We obtain this system by applying a series of dualities on the known floating brane system, imposing that it allows for the JMaRT solution. We construct an explicit multi-centre solution generalising the JMaRT solution, with an arbitrary number of additional BPS centres on a line. We describe explicitly the embedding of the JMaRT solution in this system in five dimensions.
Bossard, Guillaume
We define a new partially solvable system of equations that parametrises solutions to six-dimensional N=(1,0) ungauged supergravity coupled to tensor multiplets. We obtain this system by applying a series of dualities on the known floating brane system, imposing that it allows for the JMaRT solution. We construct an explicit multi-centre solution generalising the JMaRT solution, with an arbitrary number of additional BPS centres on a line. We describe explicitly the embedding of the JMaRT solution in this system in five dimensions.
NASA Astrophysics Data System (ADS)
Bossard, Guillaume; Katmadas, Stefanos
We define a new partially solvable system of equations that parametrises solutions to six-dimensional ungauged supergravity coupled to tensor multiplets. We obtain this system by applying a series of dualities on the known floating brane system, imposing that it allows for the JMaRT solution. We construct an explicit multi-centre solution generalising the JMaRT solution, with an arbitrary number of additional BPS centres on a line. We describe explicitly the embedding of the JMaRT solution in this system in five dimensions.
Active dielectric antenna on chip for spatial light modulation
Qiu, Ciyuan; Chen, Jianbo; Xia, Yang; Xu, Qianfan
Integrated photonic resonators are widely used to manipulate light propagation in an evanescently-coupled waveguide. While the evanescent coupling scheme works well for planar optical systems that are naturally waveguide based, many optical applications are free-space based, such as imaging, display, holographics, metrology and remote sensing. Here we demonstrate an active dielectric antenna as the interface device that allows the large-scale integration capability of silicon photonics to serve the free-space applications. We show a novel perturbation-base diffractive coupling scheme that allows a high-Q planer resonator to directly interact with and manipulate free-space waves. Using a silicon-based photonic crystal cavity whose resonance can be rapidly tuned with a p-i-n junction, a compact spatial light modulator with an extinction ratio of 9.5?dB and a modulation speed of 150?MHz is demonstrated. Method to improve the modulation speed is discussed. PMID:23152946
Active dielectric antenna on chip for spatial light modulation
NASA Astrophysics Data System (ADS)
Qiu, Ciyuan; Chen, Jianbo; Xia, Yang; Xu, Qianfan
Integrated photonic resonators are widely used to manipulate light propagation in an evanescently-coupled waveguide. While the evanescent coupling scheme works well for planar optical systems that are naturally waveguide based, many optical applications are free-space based, such as imaging, display, holographics, metrology and remote sensing. Here we demonstrate an active dielectric antenna as the interface device that allows the large-scale integration capability of silicon photonics to serve the free-space applications. We show a novel perturbation-base diffractive coupling scheme that allows a high-Q planer resonator to directly interact with and manipulate free-space waves. Using a silicon-based photonic crystal cavity whose resonance can be rapidly tuned with a p-i-n junction, a compact spatial light modulator with an extinction ratio of 9.5 dB and a modulation speed of 150 MHz is demonstrated. Method to improve the modulation speed is discussed.
Recording invertebrate nerve activation with modulated light changes
NASA Astrophysics Data System (ADS)
McCluskey, Matthew D.; Sable, Jeffrey J.; Foust, Amanda J.; Gratton, Gabriele; Rector, David M.
Optical scattering techniques have the potential to provide noninvasive measurements of neural activity with good spatial and temporal resolution. We used the lobster nerve as a model system to investigate and record event-related optical signals with a modulated light source and heterodyne detection system. We observed changes in the transmitted birefringent light intensity, corresponding with electrophysiological measurements of the action potential. The photon delay was below the detection threshold, in part due to the small size of the nerve bundle. Our system allowed us to place an upper bound on the magnitude of the phase change of 0.01�. The physiological stability of the preparation allows comprehensive characterization of biological and instrumentation noise sources for testing optical measurement systems.
Active dielectric antenna on chip for spatial light modulation.
Qiu, Ciyuan; Chen, Jianbo; Xia, Yang; Xu, Qianfan
Integrated photonic resonators are widely used to manipulate light propagation in an evanescently-coupled waveguide. While the evanescent coupling scheme works well for planar optical systems that are naturally waveguide based, many optical applications are free-space based, such as imaging, display, holographics, metrology and remote sensing. Here we demonstrate an active dielectric antenna as the interface device that allows the large-scale integration capability of silicon photonics to serve the free-space applications. We show a novel perturbation-base diffractive coupling scheme that allows a high-Q planer resonator to directly interact with and manipulate free-space waves. Using a silicon-based photonic crystal cavity whose resonance can be rapidly tuned with a p-i-n junction, a compact spatial light modulator with an extinction ratio of 9.5 dB and a modulation speed of 150 MHz is demonstrated. Method to improve the modulation speed is discussed. PMID:23152946
Spontaneous activation of light-sensitive channels in Drosophila photoreceptors
In Drosophila photoreceptors light induces phosphoinositide hydrolysis and activation of Ca(2+)-permeable plasma membrane channels, one class of which is believed to be encoded by the trp gene. We have investigated the properties of the light-sensitive channels under conditions where they are activated independently of the transduction cascade. Whole-cell voltage clamp recordings were made from photoreceptors in a preparation of dissociated Drosophila ommatidia. Within a few minutes of establishing the whole-cell configuration, there is a massive spontaneous activation of cation-permeable channels. When clamped near resting potential, this "rundown current" (RDC) accelerates over several seconds, peaks, and then relaxes to a steady- state which lasts indefinitely (many minutes). The RDC is invariably associated with a reduction in sensitivity to light by at least 100- fold. The RDC has a similar absolute magnitude, reversal potential, and voltage dependence to the light-induced current, suggesting that it is mediated by the same channels. The RDC is almost completely (> or = 98%) blocked by La3+ (10-20 microM) and is absent, or reduced and altered in the trp mutant (which lacks a La(3+)-sensitive light- dependent Ca2+ channel), suggesting that it is largely mediated by the trp-dependent channels. Power spectra of the steady-state noise in the RDC can be fitted by simple Lorentzian functions consistent with random channel openings. The variance/mean ratio of the RDC noise suggests the underlying events (channels) have conductances of approximately 1.5-4.5 pS in wild-type (WT), but 12-30 pS in trp photoreceptors. Nevertheless, the power spectra of RDC noise in WT and trp are indistinguishable, in both cases being fitted by the sum of two Lorentzians with a major time constant (effective "mean channel open time") of 1-2 ms and a minor component at higher frequencies (approximately 0.2 ms). This implies that the noise in the WT RDC may actually be dominated by non-trp- dependent channels and that the trp-dependent channels may be of even lower unit conductance. PMID:8195780
Mirage of Floating Exchange Rates
Carmen M. Reinhart
This note summarizes some of the highlights of my longer paper with Guillermo Calvo�Fear of Floating.� Many emerging market countries have suffered financial crises. One view blames soft pegs for these crises. Adherents to that view suggest that countries move to corner solutions--hard pegs or floating exchange rates. We analyze the behavior of exchange rates, reserves, and interest rates to
Mechanism of activation of light-activated phosphodiesterase and evidence for homology with hormone-activated adenylate cyclase
Bitensky, M.W.; Yamazaki, A.; Wheeler, M.A.; George, J.S.; Rasenick, M.M.
Light-activated cGMP phosphodiesterase (PDE) is one of the effector proteins in the rod outer segments in vertebrate retina. The hydrolysis of cGMP in rod occurs with a speed and light sensitivity which suggests a role for this hydrolysis in visual transduction. In fact, there is electrophysiological data which supports the possibility that cGMP could regulate rod membrane voltage. PDE shows very rapid activation in the presence of photons and GTP. We have called attention to the intriguing analogy between light activated rod phosphodiesterase and hormone activated adenylate cyclase. A number of studies have implicated the binding of GTP to a GTP binding protein as a factor in the hormone dependent activation of adenylate cyclase. Moreover, Cassel and Selinger have shown that hydrolysis of GTP is a component in the inactivation of the hormone dependent adenylate cyclase. We review here recent additional data which provide specific molecular details of the mechanism of light activation of rod PDE as well as demonstrate the exchange of components between light activated PDE and hormone activated cyclase.
Oshima, M.; Narita, H.; Tabuchi, H.; Yashima, N.
A floating offshore structure which is moored at a fixed position on the sea by means of mooring hawsers and anchors connected to the ends thereof respectively for conducting a submarine excavating operation from a deck of the structure. The structure includes a moorage hull part provided with a vertical through-hole formed therein for receiving an excavating drill pipe and the mooring hawsers and a movable hull part connected to the moorage hull part so as to be rotatable within a horizontal plane. The movable hull part is constituted as a hull defining the outer wall of the floating offshore structure and connected with the moorage hull part by inserting it into a moorage hull part receiving hole formed at a position closer to the bow thereof. The movable hull part has near its water plane a horizontal section with a substantially oval shape formed by a fore draft part in a substantially circular or polygonal shape, with the moorage hull part receiving hole as a center and an after draft part taperingly projecting aft from the fore draft part.
Asymmetric photoredox transition-metal catalysis activated by visible light
NASA Astrophysics Data System (ADS)
Huo, Haohua; Shen, Xiaodong; Wang, Chuanyong; Zhang, Lilu; R�se, Philipp; Chen, Liang-An; Harms, Klaus; Marsch, Michael; Hilt, Gerhard; Meggers, Eric
Asymmetric catalysis is seen as one of the most economical strategies to satisfy the growing demand for enantiomerically pure small molecules in the fine chemical and pharmaceutical industries. And visible light has been recognized as an environmentally friendly and sustainable form of energy for triggering chemical transformations and catalytic chemical processes. For these reasons, visible-light-driven catalytic asymmetric chemistry is a subject of enormous current interest. Photoredox catalysis provides the opportunity to generate highly reactive radical ion intermediates with often unusual or unconventional reactivities under surprisingly mild reaction conditions. In such systems, photoactivated sensitizers initiate a single electron transfer from (or to) a closed-shell organic molecule to produce radical cations or radical anions whose reactivities are then exploited for interesting or unusual chemical transformations. However, the high reactivity of photoexcited substrates, intermediate radical ions or radicals, and the low activation barriers for follow-up reactions provide significant hurdles for the development of efficient catalytic photochemical processes that work under stereochemical control and provide chiral molecules in an asymmetric fashion. Here we report a highly efficient asymmetric catalyst that uses visible light for the necessary molecular activation, thereby combining asymmetric catalysis and photocatalysis. We show that a chiral iridium complex can serve as a sensitizer for photoredox catalysis and at the same time provide very effective asymmetric induction for the enantioselective alkylation of 2-acyl imidazoles. This new asymmetric photoredox catalyst, in which the metal centre simultaneously serves as the exclusive source of chirality, the catalytically active Lewis acid centre, and the photoredox centre, offers new opportunities for the `green' synthesis of non-racemic chiral molecules.
Light-activated RNA interference in human embryonic stem cells.
Huang, Xiao; Hu, Qirui; Braun, Gary B; Pallaoro, Alessia; Morales, Demosthenes P; Zasadzinski, Joseph; Clegg, Dennis O; Reich, Norbert O
We describe a near infrared (NIR) light-activated gene silencing method in undifferentiated human embryonic stem cell (hESC) using a plasmonic hollow gold nanoshell (HGN) as the siRNA carrier. Our modular biotin-streptavidin coupling strategy enables positively charged TAT-peptide to coat oligonucleotides-saturated nanoparticles as a stable colloid formation. TAT-peptide coated nanoparticles with dense siRNA loading show efficient penetration into a wide variety of hESC cell lines. The siRNA is freed from the nanoparticles and delivered to the cytosol by femtosecond pulses of NIR light with potentially exquisite spatial and temporal control. The effectiveness of this approach is shown by targeting GFP and Oct4 genes in undifferentiated hESC (H9). The accelerated expression of differentiation markers for all three germ layers resulting from Oct4 knockdown confirms that this method has no detectable adverse effects that limit the range of differentiation. This biocompatible and NIR laser-activated patterning method makes possible single cell resolution of siRNA delivery for diverse studies in stem cell biology, tissue engineering and regenerative medicine. PMID:26086448
Floating Cities, Islands and States
Alexander Bolonkin
Many small countries are in need of additional territory. They build landfills and expensive artificial islands. The ocean covers 71 per cent of the Earth surface. Those countries (or persons of wealth) starting the early colonization of the ocean may obtain advantages through additional territory or creating their own independent state. An old idea is building a big ship. The best solution to this problem, however, is the provision of floating cities, islands, and states. The author idea is to use for floating cities, islands, and states a cheap floating platform created from a natural ice field taken from the Arctic or Antarctic oceans. These cheap platforms protected by air-film (bottom and sides) and a conventional insulating cover (top) and having a cooling system can exist for an unlimited time. They can be increased in number or size at any time, float in warm oceans, travel to different continents and countries, serve as artificial airports, harbors and other marine improvements, as well as floating cities and industrial bases for virtually any use. Author researches and computes parameters of these ice floating platforms, other methods of building such floating territory, compares them and shows that the offered method is the most cheap and efficient means of ocean colonization.
Profiling floating point value ranges for reconfigurable
Kelly, Paul H. J.
Profiling floating point value ranges for reconfigurable implementation Ashley W Brown, Paul H J of floating-point arithmetic. This paper presents FloatWatch, a dynamic execution profiling tool designed to identify where an application can benefit from reduced precision or re- duced range in floating
Tamm floating electron in nanodiamond
Ivan A. Denisov; Peter I. Belobrov
Nanodiamond exhibits unpaired electrons in magnetization, EPR, NMR and Auger relaxation. Wave functions and eigenenergies of a bound electron in a nanodiamond crystal have been calculated. It has been proved by using quantum mechanical analysis that unpaired electrons are self-condition of a nanodiamond as a limited crystal according to Tamm theory of surface states. The surface electron floating over a nanodiamond gives paramagnetic response and stabilizes the nanoparticle at small range of size. Possibly the spin of the floating electron can be used for floating point calculation in future quantum computers on the base of nanodiamond qubits.
Floating--Point Fused Multiply--Add: Reduced Latency for Floating-Point Addition
California at Davis, University of
Floating--Point Fused Multiply--Add: Reduced Latency for Floating-Point Addition Javier D for the computation of the double--precision floating--point multiply--add fused (MAF) operation A + (B �? C) that permits to compute the floating--point addition with lower latency than floating--point multiplication
46 CFR 117.137 - Stowage of life floats and buoyant apparatus.
Code of Federal Regulations, 2014 CFR
...of a dark color or of a type certified to be resistant to deterioration from ultraviolent light; and (3) If metal, be corrosion resistant. (d) If the life float or buoyant apparatus does not have a painter attachment fitting, a...
46 CFR 117.137 - Stowage of life floats and buoyant apparatus.
Code of Federal Regulations, 2010 CFR
...of a dark color or of a type certified to be resistant to deterioration from ultraviolent light; and (3) If metal, be corrosion resistant. (d) If the life float or buoyant apparatus does not have a painter attachment fitting, a...
46 CFR 117.137 - Stowage of life floats and buoyant apparatus.
Code of Federal Regulations, 2011 CFR
...of a dark color or of a type certified to be resistant to deterioration from ultraviolent light; and (3) If metal, be corrosion resistant. (d) If the life float or buoyant apparatus does not have a painter attachment fitting, a...
46 CFR 117.137 - Stowage of life floats and buoyant apparatus.
Code of Federal Regulations, 2013 CFR
...of a dark color or of a type certified to be resistant to deterioration from ultraviolent light; and (3) If metal, be corrosion resistant. (d) If the life float or buoyant apparatus does not have a painter attachment fitting, a...
46 CFR 117.137 - Stowage of life floats and buoyant apparatus.
Code of Federal Regulations, 2012 CFR
...of a dark color or of a type certified to be resistant to deterioration from ultraviolent light; and (3) If metal, be corrosion resistant. (d) If the life float or buoyant apparatus does not have a painter attachment fitting, a...
Visible-Light-Induced Bactericidal Activity of a Nitrogen-Doped Titanium Photocatalyst against Human Pathogens
Ming-Show Wong; Wen-Chen Chu; Der-Shan Sun; Hsuan-Shun Huang; Jiann-Hwa Chen; Pei-Jane Tsai; Nien-Tsung Lin; Mei-Shiuan Yu; Shang-Feng Hsu; Shih-Lien Wang; Hsin-Hou Chang
The antibacterial activity of photocatalytic titanium dioxide (TiO2) substrates is induced primarily by UV light irradiation. Recently, nitrogen- and carbon-doped TiO2 substrates were shown to exhibit photocatalytic activities under visible-light illumination. Their antibacterial activity, however, remains to be quantified. In this study, we demonstrated that nitrogen-doped TiO2 substrates have superior visible-light-induced bactericidal activity against Escherichia coli compared to pure TiO2
Floating orbital molecular dynamics simulations.
Perlt, Eva; Br�ssel, Marc; Kirchner, Barbara
We introduce an alternative ab initio molecular dynamics simulation as a unification of Hartree-Fock molecular dynamics and the floating orbital approach. The general scheme of the floating orbital molecular dynamics method is presented. Moreover, a simple but sophisticated guess for the orbital centers is provided to reduce the number of electronic structure optimization steps at each molecular dynamics step. The conservation of total energy and angular momentum is investigated in order to validate the floating orbital molecular dynamics approach with and without application of the initial guess. Finally, a water monomer and a water dimer are simulated, and the influence of the orbital floating on certain properties like the dipole moment is investigated. PMID:24600690
NULL Convention Floating Point Multiplier
Ramachandran, Seshasayanan
Floating point multiplication is a critical part in high dynamic range and computational intensive digital signal processing applications which require high precision and low power. This paper presents the design of an IEEE 754 single precision floating point multiplier using asynchronous NULL convention logic paradigm. Rounding has not been implemented to suit high precision applications. The novelty of the research is that it is the first ever NULL convention logic multiplier, designed to perform floating point multiplication. The proposed multiplier offers substantial decrease in power consumption when compared with its synchronous version. Performance attributes of the NULL convention logic floating point multiplier, obtained from Xilinx simulation and Cadence, are compared with its equivalent synchronous implementation. PMID:25879069
Skylab floating ice experiment
NASA Technical Reports Server (NTRS)
Campbell, W. J. (principal investigator); Ramseier, R. O.; Weaver, R. J.; Weeks, W. F.
The author has identified the following significant results. Coupling of the aircraft data with the ground truth observations proved to be highly successful with interesting results being obtained with IR and SLAR passive microwave techniques, and standard photography. Of particular interest were the results of the PMIS system which operated at 10.69 GHz with both vertical and horizontal polarizations. This was the first time that dual polarized images were obtained from floating ice. In both sea and lake ice, it was possible to distinguish a wide variety of thin ice types because of their large differences in brightness temperatures. It was found that the higher brightness temperature was invariably obtained in the vertically polarized mode, and as the age of the ice increases the brightness temperature increases in both polarizations. Associated with this change in age, the difference in temperature was observed as the different polarizations decreased. It appears that the horizontally polarized data is the most sensitive to variations in ice type for both fresh water and sea ice. The study also showed the great amount of information on ice surface roughness and deformation patterns that can be obtained from X-band SLAR observations.
Some Activities with Polarized Light from a Laptop LCD Screen
ERIC Educational Resources Information Center
Fakhruddin, Hasan
The LCD screen of a laptop computer provides a broad, bright, and extended source of polarized light. A number of demonstrations on the properties of polarized light from a laptop computer screens are presented here.
Analysis and control of the active area scaling effect on white organic light emitting diodes towards lighting applications
C. Piliego; M. Mazzeo; M. Salerno; R. Cingolani; G. Gigli; A. Moro
The authors investigate the scaling of the performances on white organic light emitting diode in devices having active regions ranging from 0.25 to 9 cm2. They observe a drop in the luminance and in the current density with increasing active area of the devices. A model where both these effects are ascribed to the spread of the current leakage on
Clinical Features: Patients with Floating Harbor syndrome [OMIM #136140] typically have short stature, delayed osseous
Ober, Carole
Activator Protein, Cause Floating Harbor Syndrome." (2012) Am J Hum Genet 90(2): 308-313. 2. White S et al1/13 Clinical Features: Patients with Floating Harbor syndrome [OMIM #136140] typically have short of affected individuals include a triangular shaped face, short philtrum, wide mouth, and a long nose
Optimization of float use in risk analysis-based network scheduling
Daji Gong
Floats are often used in project networks for resource allocations and as an alternative for reducing project costs without causing negative impact on project duration. However, when the time uncertainties of non-critical activities are great, the use of floats can lead to an increased risk of project schedule overruns, and accordingly an increase in project costs. This paper presents a
Engineering of a red-light�activated human cAMP/cGMP-specific phosphodiesterase
Gasser, Carlos; Taiber, Sandra; Yeh, Chen-Min; Wittig, Charlotte Helene; Hegemann, Peter; Ryu, Soojin; Wunder, Frank; M�glich, Andreas
Sensory photoreceptors elicit vital physiological adaptations in response to incident light. As light-regulated actuators, photoreceptors underpin optogenetics, which denotes the noninvasive, reversible, and spatiotemporally precise perturbation by light of living cells and organisms. Of particular versatility, naturally occurring photoactivated adenylate cyclases promote the synthesis of the second messenger cAMP under blue light. Here, we have engineered a light-activated phosphodiesterase (LAPD) with complementary light sensitivity and catalytic activity by recombining the photosensor module of Deinococcus radiodurans bacterial phytochrome with the effector module of Homo sapiens phosphodiesterase 2A. Upon red-light absorption, LAPD up-regulates hydrolysis of cAMP and cGMP by up to sixfold, whereas far-red light can be used to down-regulate activity. LAPD also mediates light-activated cAMP and cGMP hydrolysis in eukaryotic cell cultures and in zebrafish embryos; crucially, the biliverdin chromophore of LAPD is available endogenously and does not need to be provided exogenously. LAPD thus establishes a new optogenetic modality that permits light control over diverse cAMP/cGMP-mediated physiological processes. Because red light penetrates tissue more deeply than light of shorter wavelengths, LAPD appears particularly attractive for studies in living organisms. PMID:24889611
14 CFR 29.757 - Hull and auxiliary float strength.
Code of Federal Regulations, 2010 CFR
...2010-01-01 2010-01-01 false Hull and auxiliary float strength. 29.757 Section 29... Floats and Hulls � 29.757 Hull and auxiliary float strength. The hull, and auxiliary floats if used, must withstand the...
LATEX-Paragraphs Floating around Figures Thomas Kneser
LATEX-Paragraphs Floating around Figures Thomas `float' in paragraphs. T* *his article presents the LATEX style option FLOATFIG which can be used with paragraphs floating around them. For such obje* *cts Th. Reid has chosen the term `Floating Figures
NSDL National Science Digital Library
Miss Massey
Have you ever wondered how light works? Today, you will be light detectives investigating how light works! Follow the links below to help your investigation! As you are reading about light, write down any words that you do not know. Use the dictionary link to find definitions. Write down their definitions as you find them. First, you will need to know some Light Basics Find out more about light with Light Fun Facts Want to know how glasses help people see? Go to Light and Lenses Look up any unknown words atWebster s Word Central ...
Planet signatures in collisionally active debris discs: scattered light images
NASA Astrophysics Data System (ADS)
Thebault, P.; Kral, Q.; Ertel, S.
Context. Planet perturbations have been often invoked as a potential explanation for many spatial structures that have been imaged in debris discs. So far this issue has been mostly investigated with pure N-body numerical models, which neglect the crucial effect collisions within the disc can have on the disc's response to dynamical perturbations. Aims: We numerically investigate how the coupled effect of collisions and radiation pressure can affect the formation and survival of radial and azimutal structures in a disc perturbed by a planet. We consider two different set-ups: a planet embedded within an extended disc and a planet exterior to an inner debris ring. One important issue we want to address is under which conditions a planet's signature can be observable in a collisionally active disc. Methods: We use our DyCoSS code, which is designed to investigate the structure of perturbed debris discs at dynamical and collisional steady-state, and derive synthetic images of the system in scattered light. The planet's mass and orbit, as well as the disc's collisional activity (parameterized by its average vertical optical depth ?0) are explored as free parameters. Results: We find that collisions always significantly damp planet-induced spatial structures. For the case of an embedded planet, the planet's signature, mostly a density gap around its radial position, should remain detectable in head-on images if Mplanet ? MSaturn. If the system is seen edge-on, however, inferring the presence of the planet is much more difficult, as only weak asymmetries remain in a collisionally active disc, although some planet-induced signatures might be observable under very favourable conditions. For the case of an inner ring and an external planet, planetary perturbations cannot prevent collision-produced small fragments from populating the regions beyond the ring. The radial luminosity profile exterior to the ring is in most cases close to the one it should have in the absence of the external planet. The most significant signature left by a Jovian planet on a circular orbit are precessing azimutal structures that can be used to indirectly infer its presence. For a planet on an eccentric orbit, we show that the ring becomes elliptic and that the well known pericentre glow effect is visible despite of collisions and radiation pressure, but that detecting such features in observed discs is not an unambiguous indicator of the presence of an outer planet. Movies are available in electronic form at http://www.aanda.org
Active Matrix Organic Light Emitting Diode (AMOLED) Environmental Test Report
NASA Technical Reports Server (NTRS)
Salazar, George A.
This report focuses on the limited environmental testing of the AMOLED display performed as an engineering evaluation by The NASA Johnson Space Center (JSC)-specifically. EMI. Thermal Vac, and radiation tests. The AMOLED display is an active-matrix Organic Light Emitting Diode (OLED) technology. The testing provided an initial understanding of the technology and its suitability for space applications. Relative to light emitting diode (LED) displays or liquid crystal displays (LCDs), AMOLED displays provide a superior viewing experience even though they are much lighter and smaller, produce higher contrast ratio and richer colors, and require less power to operate than LCDs. However, AMOLED technology has not been demonstrated in a space environment. Therefore, some risks with the technology must be addressed before they can be seriously considered for human spaceflight. The environmental tests provided preliminary performance data on the ability of the display technology to handle some of the simulated induced space/spacecraft environments that an AMOLED display will see during a spacecraft certification test program. This engineering evaluation is part of a Space Act Agreement (SM) between The NASA/JSC and Honeywell International (HI) as a collaborative effort to evaluate the potential use of AMOLED technology for future human spaceflight missions- both government-led and commercial. Under this SM, HI is responsible for doing optical performance evaluation, as well as temperature and touch screen studies. The NASA/JSC is responsible for performing environmental testing comprised of EMI, Thermal Vac, and radiation tests. Additionally, as part of the testing, limited optical data was acquired to assess performance as the display was subjected to the induced environments. The NASA will benefit from this engineering evaluation by understanding AMOLED suitability for future use in space as well as becoming a smarter buyer (or developer) of the technology. HI benefits from the environmental testing results by understanding its performance limitations/shortcomings to improve subsequent generations of AMOLED technology. Note that the AMOLED used in this test was not deSigned for the space environment but rather for commercial/industrial terrestrial applications.
Possible Control of Maize Leaf Sucrose-Phosphate Synthase Activity by Light Modulation
Sicher, Richard C.; Kremer, Diane F.
Sucrose phosphate synthase (SPS) activity was measured in extracts of maize (Zea mays L.) and soybean (Glycine max L. [Merr.]) leaves over a single day/night cycle. There was a 2- to 3-fold postillumination increase in extractable enzyme activity in maize leaves, whereas the activity of soybean SPS was only about 30% higher in extracts prepared from light- compared to dark-adapted leaves. Alterations in extractable maize leaf SPS activity correlated with light/dark transitions suggesting that the enzyme may be light modulated. Diurnal variations of extractable maize leaf SPS activity were also observed in a greenhouse experiment. A transition from high (light) to low (dark) extractable SPS activity occurred near the light compensation point for photosynthesis (about 20 micromole photons per square meter per second). Further increases in irradiance did not increase extractable SPS activity. Substrate affinities for uridine 5?-diphosphoglucose (Michaelis constant = 3.5 and 5.1 millimolar) and fructose-6 phosphate (half maximal concentration = 1.0 and 2.5 millimolar) were lower for partially purified SPS obtained from light compared to dark acclimated maize leaves. Light-induced changes in extractable SPS activity were stable for at least one column chromatography step. The above results indicate that light-induced changes in SPS activity may be important in controlling the photosynthetic production of sucrose. PMID:16664475
Detection of Floating Inputs in Logic Circuits
NASA Technical Reports Server (NTRS)
Cash, B.; Thornton, M. G.
Simple modification of oscilloscope probe allows easy detection of floating inputs or tristate outputs in digital-IC's. Oscilloscope probe easily modified with 1/4 W resistor and switch for detecting floating inputs in CMOS logic circuits.
Flexible dynamics of floating wind turbines
Luypaert, Thomas (Thomas J.)
This work presents Tower Flex, a structural dynamics model for a coupled analysis of offshore floating wind turbines consisting of a tower, a floating platform and a mooring system. In this multi-body, linear frequency-domain ...
Nanoflare Properties throughout Active Regions: Comparing SDO/AIA Observations with Modeled Active Region Light Curves
NASA Technical Reports Server (NTRS)
Viall, Nicholeen
Coronal plasma in active regions is typically measured to be at temperatures near 1-3 MK. Is the majority of the coronal plasma in hydrostatic equilibrium, maintained at these temperatures through a form of quasi-steady heating, or is this simply a measure of the average temperature of widely varying, impulsively heated coronal plasma? Addressing this question is complicated by the fact that the corona is optically thin: many thousands of flux tubes which are heated completely independently are contributing to the total emission along a given line of sight. There is a large body of work focused on the heating of isolated features - coronal loops - which are impulsively heated, however it is the diffuse emission between loops which often comprises the majority of active region emission. Therefore in this study we move beyond isolated features and analyze all of the emission in an entire active region from all contributing flux tubes. We investigate light curves systematically using SDO/AIA observations. We also model the active region corona as a line-of-sight integration of many thousands of completely independently heated flux tubes. The emission from these flux tubes may be time dependent, quasi-steady, or a mix of both, depending on the cadence of heat release. We demonstrate that despite the superposition of randomly heated flux tubes, different distributions of nanoflare cadences produce distinct signatures in light curves observed with multi-wavelength and high time cadence data, such as those from SDO/AIA. We conclude that the majority of the active region plasma is not maintained in hydrostatic equilibrium, rather it is undergoing dynamic heating and cooling cycles. The observed emission is consistent with heating through impulsive nanoflares, whose energy is a function of location within the active region.
Light/dark modulation of enzyme activity in developing barley leaves
Sibley, M.H.; Anderson, L.E. (Univ. of Illinois, Chicago (USA))
Light/dark modulation of the ribulose-5-phosphate kinase, NADP{sup +}-glyceraldehyde-3-phosphate dehydrogenase, and fructose-1,6-bisphosphatase activity was measured in the developing primary leaf of barley (Hordeum vulgare L.) seedlings. Ribulose-5-phosphate kinase and NADP{sup +}-glyceraldehyde-3-phosphate dehydrogenase were fully light activated even at the earliest developmental stage sampled. In contrast, light modulation of fructose-1,6-bisphosphatase exhibited a complex response to leaf developmental status. Light stimulation of fructose-1,6-bisphosphatase activity (measured at pH 8.0) increased progressively during leaf development. On the other hand, acid fructose-1,6-bisphosphatase activity (measured at pH 6.0) was inhibited by light, and this light inhibition was greater in the base of the leaf than in the tip of the leaf.
CS61C Fall 2011 Floating Point and CALL -Notes modified from Fall 2010 Floating Point
California at Irvine, University of
CS61C Fall 2011 Floating Point and CALL - Notes modified from Fall 2010 Floating Point /* 100 thousand */ #define INCREMENT .00003f /* 3 hundred thousandths */ int main(void) { int i; float x = 0.f; for (i = 0; i float result = (x - 3.f)/3.f; printf
40 CFR 65.45 - External floating roof converted into an internal floating roof.
Code of Federal Regulations, 2013 CFR
...2013-07-01 2013-07-01 false External floating roof converted into an internal floating roof. 65.45 Section 65.45 Protection...RULE Storage Vessels � 65.45 External floating roof converted into an internal floating...
40 CFR 65.45 - External floating roof converted into an internal floating roof.
Code of Federal Regulations, 2011 CFR
...2011-07-01 2011-07-01 false External floating roof converted into an internal floating roof. 65.45 Section 65.45 Protection...RULE Storage Vessels � 65.45 External floating roof converted into an internal floating...
40 CFR 65.45 - External floating roof converted into an internal floating roof.
Code of Federal Regulations, 2012 CFR
...2012-07-01 2012-07-01 false External floating roof converted into an internal floating roof. 65.45 Section 65.45 Protection...RULE Storage Vessels � 65.45 External floating roof converted into an internal floating...
40 CFR 65.45 - External floating roof converted into an internal floating roof.
Code of Federal Regulations, 2014 CFR
...2014-07-01 2014-07-01 false External floating roof converted into an internal floating roof. 65.45 Section 65.45 Protection...RULE Storage Vessels � 65.45 External floating roof converted into an internal floating...
40 CFR 65.45 - External floating roof converted into an internal floating roof.
Code of Federal Regulations, 2010 CFR
...2010-07-01 2010-07-01 false External floating roof converted into an internal floating roof. 65.45 Section 65.45 Protection...RULE Storage Vessels � 65.45 External floating roof converted into an internal floating...
Why Do Countries Float the Way They Float?
Ricardo Hausmann; Ugo G. Panizza; Ernesto Hugo Stein
Countries that are classified as having floating exchange rate systems (or very wide bands) show strikingly different patterns of behavior. They hold very different levels of international reserves and allow very different volatilities in the movements of the exchange rate relative to the volatility that they tolerate either on the level of reserves or in interest rates. We document these
Why do countries float the way they float?
Ricardo Hausmann; Ugo Panizza; Ernesto Stein
Countries that are classified as having floating exchange rate systems (or very wide bands) show strikingly different patterns of behavior. They hold very different levels of international reserves and allow very different volatilities to the movements of the exchange rate relative to the volatility that they tolerate either on the level of reserves or on interest rates. We document these
Gibberellins negatively regulate light-induced nitrate reductase activity in Arabidopsis seedlings.
Zhang, Yongqiang; Liu, Zhongjuan; Liu, Rongzhi; Wang, Liguang; Bi, Yurong
In the present study, the role of phytohormone gibberellins (GAs) on regulating the nitrate reductase (NR) activity was tested in Arabidopsis seedlings. The NR activity in light-grown Col-0 seedlings was reduced by exogenous GA? (an active form of GAs), but enhanced by exogenous paclobutrazol (PAC, a gibberellin biosynthesis inhibitor), suggesting that GAs negatively regulate the NR activity in light-grown seedlings. Light is known to influence the NR activity through both photosynthesis and phytochromes. When etiolated seedlings were transferred to white or red light, both exogenously applied GA? and PAC were found to function on the NR activity only in the presence of sucrose, implying that GAs are not involved in light signaling-induced but negatively regulate photoproducts-induced NR activity. NR is regulated by light mainly at two levels: transcript level and post-translational level. Our reverse transcription (RT)-PCR assays showed that GAs did not affect the transcript levels of NIA1 and NIA2, two genes that encode NR proteins. But the divalent cations (especially Mg�?) were required for GAs negative regulation of NR activity, in view of the importance of divalent cations during the process of post-translational regulation of NR activity, which indicates that GAs very likely regulate the NR activity at the post-translational level. In the following dark-light shift analyses, GAs were found to accelerate dark-induced decrease, but retard light-induced increase of the NR activity. Furthermore, it was observed that application of G? or PAC could impair diurnal variation of the NR activity. These results collectively indicate that GAs play a negative role during light regulation of NR activity in nature. PMID:21856037
Offloading Floating Car Data Razvan Stanica
Fiore, Marco
Offloading Floating Car Data Razvan Stanica Universit�e de Lyon, INRIA UrbaNet INSA-Lyon, CITI Lab Malandrino DET Politecnico di Torino firstname.lastname@example.com Abstract--Floating Car Data (FCD) is currently network by up to 95%. I. INTRODUCTION Floating Car Data (FCD) consist of information generated by moving
32 CFR 935.165 - Floating objects.
Code of Federal Regulations, 2013 CFR
...2013-07-01 2013-07-01 false Floating objects. 935.165 Section 935...CODE Public Safety � 935.165 Floating objects. No person may anchor, moor, or beach any boat, barge, or other floating object on Wake Island in any location...
Floating Point Representation Michael L. Overton
Stein, William
Floating Point Representation Michael L. Overton copyright c fl1996 1 Computer Representation of Numbers Computers which work with real arithmetic use a system called floating point. Suppose a real : : :) 2 : To store a number in floating point representation, a computer word is divided into 3 fields
Accurate and Efficient Algorithms for Floating
Koev, Plamen
i i Accurate and Efficient Algorithms for Floating Point Computation J. Demmel and P. Koev 1 expressions containing floating point numbers, and for computing matrix factorizations (like LU, the singular is challenging because our accuracy demand is much stricter than usual. The classes of floating point expressions
32 CFR 935.165 - Floating objects.
Code of Federal Regulations, 2014 CFR
...2014-07-01 2014-07-01 false Floating objects. 935.165 Section 935...CODE Public Safety � 935.165 Floating objects. No person may anchor, moor, or beach any boat, barge, or other floating object on Wake Island in any location...
32 CFR 935.165 - Floating objects.
Code of Federal Regulations, 2012 CFR
...2012-07-01 2012-07-01 false Floating objects. 935.165 Section 935...CODE Public Safety � 935.165 Floating objects. No person may anchor, moor, or beach any boat, barge, or other floating object on Wake Island in any location...
32 CFR 935.165 - Floating objects.
Code of Federal Regulations, 2011 CFR
...2011-07-01 2011-07-01 false Floating objects. 935.165 Section 935...CODE Public Safety � 935.165 Floating objects. No person may anchor, moor, or beach any boat, barge, or other floating object on Wake Island in any location...
32 CFR 935.165 - Floating objects.
Code of Federal Regulations, 2010 CFR
...2010-07-01 2010-07-01 false Floating objects. 935.165 Section 935...CODE Public Safety � 935.165 Floating objects. No person may anchor, moor, or beach any boat, barge, or other floating object on Wake Island in any location...
New Directions in Floating-Point Arithmetic
NASA Astrophysics Data System (ADS)
Beebe, Nelson H. F.
This article briefly describes the history of floating-point arithmetic, the development and features of IEEE standards for such arithmetic, desirable features of new implementations of floating-point hardware, and discusses work-in-progress aimed at making decimal floating-point arithmetic widely available across many architectures, operating systems, and programming languages.
Light Activation of Staphylococcus aureus Toxin YoeBSa1 Reveals Guanosine-Specific Endoribonuclease Activity
Larson, Amy S.; Hergenrother, Paul J.
The Staphylococcus aureus chromosome harbors two homologues of the YefM-YoeB toxin-antitoxin (TA) system. The toxins YoeBSa1 and YoeBSa2 possess ribosome-dependent ribonuclease (RNase) activity in Escherichia coli. This activity is similar to that of the E. coli toxin YoeBEc, an enzyme that, in addition to ribosome-dependent RNase activity, possesses ribosome-independent RNase activity in vitro. To investigate whether YoeBSa1 is also a ribosome-independent RNase, YoeBSa1 was expressed using a novel strategy, and its in vitro RNase activity, sequence specificity, and kinetics were characterized. Y88 of YoeBSa1 was critical for in vitro activity and cell culture toxicity. This residue was mutated to ortho-nitrobenzyl tyrosine (ONBY) via unnatural amino acid mutagenesis. YoeBSa1-Y88ONBY could be expressed in the absence of the antitoxin YefMSa1 in E. coli. Photocaged YoeBSa1-Y88ONBY displayed UV light-dependent RNase activity toward free mRNA in vitro. The in vitro ribosome-independent RNase activity of YoeBSa1-Y88ONBY, YoeBSa1-Y88F, and YoeBSa1-Y88TAG was significantly reduced or abolished. In contrast to YoeBEc, which cleaves RNA at both adenosine and guanosine with a preference for adenosine, YoeBSa1 cleaved mRNA specifically at guanosine. Using this information, a fluorometric assay was developed and used to determine the kinetic parameters for ribosome-independent RNA cleavage by YoeBSa1. PMID:24279911
NASA Technical Reports Server (NTRS)
Williams, Robert L., Sr.; Williams, Robert L., Jr.; Chase, Timothy L.
Tool fits out-of-round seal groove and laps it to fine finish without binding. Includes floating lapping pieces riding freely in groove, and are curved to match nominal diameter of groove. One lapping piece tightened so it does not move relative to disk.
The Floating Siphon - an Effective
Alexander Kolchinski
A simple device, which can be used in place of a syringe pump, has been suggested for high dilution experiments. The flasks containing the solutions to be mixed are equipped with siphons and placed on the top of a styrofoam cylinder, or other floater. The styrofoam cylinder floats in a beaker containing water. A glass rod is threaded through a
Integrated floating point signal processor
K. Bottcher; A. Lacroix; M. Talmi; D. Wesseling
Recent advances in technology of VLSI circuits enable economical hardware implementation of highly sophisticated signal processing algorithms. This provides the capability of realising a signal processor with uniform hardware for wide real-time applications. The adaption of the VLSI circuits to special application is possible by appropriate microprograms. The processor speed is determined by the arithmetic unit, particularly if floating point
A Variable Light Domain Fluorogen Activating Protein Homodimerizes to Activate Dimethylindole Red�
Senutovitch, Nina; Stanfield, Robyn L.; Bhattacharyya, Shantanu; Rule, Gordon S.; Wilson, Ian A.; Armitage, Bruce A.; Waggoner, Alan S.; Berget, Peter B.
Novel fluorescent tools such as green fluorescent protein analogs and Fluorogen Activating Proteins (FAPs) are useful in biological imaging to track protein dynamics in real-time with low fluorescence background. FAPs are single-chain variable fragments (scFvs) selected from a yeast surface display library that produce fluorescence upon binding a specific dye or fluorogen that is normally not fluorescent when present in solution. FAPs generally consist of human immunoglobulin variable heavy (VH) and variable light (VL) domains covalently attached via a glycine and serine rich linker. Previously, we determined that the yeast surface clone, VH-VL M8, could bind and activate the fluorogen dimethylindole red (DIR), but that the fluorogen activation properties were localized to the M8VL domain. We report here that both NMR and X-ray diffraction methods indicate the M8VL forms non-covalent, anti-parallel homodimers that are the fluorogen activating species. The M8VL homodimers activate DIR by restriction of internal rotation of the bound dye. These structural results, together with directed evolution experiments of both VH-VL M8 and M8VL, led us to rationally design tandem, covalent homodimers of M8VL domains joined by a flexible linker that have a high affinity for DIR and good quantum yield. PMID:22390683
A variable light domain fluorogen activating protein homodimerizes to activate dimethylindole red.
Senutovitch, Nina; Stanfield, Robyn L; Bhattacharyya, Shantanu; Rule, Gordon S; Wilson, Ian A; Armitage, Bruce A; Waggoner, Alan S; Berget, Peter B
Novel fluorescent tools such as green fluorescent protein analogues and fluorogen activating proteins (FAPs) are useful in biological imaging for tracking protein dynamics in real time with a low fluorescence background. FAPs are single-chain variable fragments (scFvs) selected from a yeast surface display library that produce fluorescence upon binding a specific dye or fluorogen that is normally not fluorescent when present in solution. FAPs generally consist of human immunoglobulin variable heavy (V(H)) and variable light (V(L)) domains covalently attached via a glycine- and serine-rich linker. Previously, we determined that the yeast surface clone, V(H)-V(L) M8, could bind and activate the fluorogen dimethylindole red (DIR) but that the fluorogen activation properties were localized to the M8V(L) domain. We report here that both nuclear magnetic resonance and X-ray diffraction methods indicate the M8V(L) forms noncovalent, antiparallel homodimers that are the fluorogen activating species. The M8V(L) homodimers activate DIR by restriction of internal rotation of the bound dye. These structural results, together with directed evolution experiments with both V(H)-V(L) M8 and M8V(L), led us to rationally design tandem, covalent homodimers of M8V(L) domains joined by a flexible linker that have a high affinity for DIR and good quantum yields. PMID:22390683
Blue light irradiation affects anthocyanin content and enzyme activities involved in postharvest strawberry fruit.
Xu, Feng; Cao, Shifeng; Shi, Liyu; Chen, Wei; Su, Xinguo; Yang, Zhenfeng
Blue light irradiation was applied to postharvest strawberry fruit to explore its influence on anthocyanin content and anthocyanin biosynthetic enzyme activities. Strawberry fruit was irradiated with blue light at 40 ?mol m(-2) s(-1) for 12 days at 5 �C. The results indicated that blue light treatment improved total anthocyanin content in strawberry fruit during storage. Meanwhile, the treatment increased the activities of glucose-6-phosphate, shikimate dehydrogenase, tyrosine ammonia-lyase, phenylalanine ammonia-lyase, cinnamate-4-hydroxylase, 4-coumarate/coenzyme A ligase, dihydroflavonol-4-reductase, chalcone synthase, flavanone-3-?-hydroxylase, anthocyanin synthase, and UDP-glycose flavonoid-3-O-glycosyltranferase, which suggested that the enhancement of anthocyanin concentration by blue light might result from the activation of its related enzymes. Blue light might be proposed as a supplemental light source in the storage of strawberry fruit to improve its anthocyanin content. PMID:24783962
Growth of a floating aquatic weed, Salvinia under standard conditions
John J. Gaudet
1.Growth of the floating aquatic weed, Salvinia, in sterile culture was exponential for at least 2 weeks under standardized conditions.2.Increase in light intensity or in CO2 resulted in increases in growth rate, but did not extend the exponential period of growth.3.This aquatic plant, like many others, discriminates against calcium relative to strontium.4.In culture Salvinia exhibited luxury consumption of N and
Mitogen-Activated Protein Kinase Kinase 3 Is Required for Regulation during Dark-Light Transition
Lee, Horim
Plant growth and development are coordinately orchestrated by environmental cues and phytohormones. Light acts as a key environmental factor for fundamental plant growth and physiology through photosensory phytochromes and underlying molecular mechanisms. Although phytochromes are known to possess serine/threonine protein kinase activities, whether they trigger a signal transduction pathway via an intracellular protein kinase network remains unknown. In analyses of mitogen-activated protein kinase kinase (MAPKK, also called MKK) mutants, the mkk3 mutant has shown both a hypersensitive response in plant hormone gibberellin (GA) and a less sensitive response in red light signaling. Surprisingly, light-induced MAPK activation in wild-type (WT) seedlings and constitutive MAPK phosphorylation in dark-grown mkk3 mutant seedlings have also been found, respectively. Therefore, this study suggests that MKK3 acts in negative regulation in darkness and in light-induced MAPK activation during dark-light transition. PMID:26082029
Light Travel Time and the Size of Active Galaxies
NSDL National Science Digital Library
Using real data from NASA's Fermi satellite, students determine the size and energy of an active galaxy flare region. This activity includes background information for teachers, student worksheets, procedures, adaptations, extensions, an assessment rubric, and related resources. This is activity 3 of 3 in the "Active Galaxies Educator's Guide."
NSDL National Science Digital Library
Mr. Scholer
Lighting is one of the key elements used in cinematography. This unit will demonstrate the basic concepts and theory behind lighting which you will use in your future video projects. State Standard 3 - The student will be able to understand and demonstrate lighting systems and how they are used. Objective - At the conclusion of this unit you be able to demonstrate a three-point lighting setup. You will also be able to define each of the following terms and ...
NSDL National Science Digital Library
nancy thill
This activity is a classroom lab where students learn that cold water is denser and hot water is less dense than room temperature water. Students perform an experiment and relate to their background knowledge to make conjectures.
NSDL National Science Digital Library
Cody Taylor
Learners create beautiful fluid motion. They explore fluid dynamics, surface tension, solubility, and buoyancy while mixing liquids together. Learners can photograph or film the fluid motion for analysis as well. This activity is also suitable as a demonstration. Learners can continue their investigations by completing the related activity "Density Rainbow and the Great Viscosity Race." Resource contains vocabulary definitions, detailed background information, and suggestions for assessment and extensions.
Temporal and spatial distribution of floating objects in coastal waters of central-southern Chile and Patagonian fjords
NASA Astrophysics Data System (ADS)
Hinojosa, Iv�n A.; Rivadeneira, Marcelo M.; Thiel, Martin
Floating objects are suggested to be the principal vector for the transport and dispersal of marine invertebrates with direct development as well as catalysts for carbon and nutrient recycling in accumulation areas. The first step in identifying the ecological relevance of floating objects in a specific area is to identify their spatio-temporal distribution. We evaluated the composition, abundance, distribution, and temporal variability of floating objects along the continental coast of central-southern Chile (33-42�S) and the Patagonian fjords (42-50�S) using ship surveys conducted in austral winter (July/August) and spring (November) of the years 2002-2005 and 2008. Potential sources of floating items were identified with the aid of publicly available databases and scientific reports. We found three main types of floating objects, namely floating marine debris (mainly plastic objects and Styrofoam), wood (trunks and branches), and floating kelps ( Macrocystis pyrifera and Durvillaea antarctica). Floating marine debris were abundant along most of the examined transects, with markedly lower abundances toward the southern fjord areas. Floating marine debris abundances generally corresponded to the distribution of human activities, and were highest in the Interior Sea of Chilo�, where aquaculture activities are intense. Floating wood appeared sporadically in the study area, often close to the main rivers. In accordance with seasonal river run-off, wood was more abundant along the continental coast in winter (rainy season) and in the Patagonian fjords during the spring surveys (snow melt). Densities of the two floating kelp species were similar along the continental coast, without a clear seasonal pattern. M. pyrifera densities increased towards the south, peaking in the Patagonian fjords, where it was dominant over D. antarctica. Densities of M. pyrifera in the Patagonian fjords were highest in spring. Correlation analyses between the abundances of floating objects and the distance to the nearest sources were generally non-significant, suggesting that post-supply processes affect the distribution of the floating objects in the study region. The identification of several major retention zones supports this idea. Accumulation areas of floating objects appear to be more common in the fjord zones. In general, the results underscore the abundance of floating objects throughout the study region and the fact that floating marine debris sources are mostly local, whereas floating algae may be dispersed over greater distances. Future studies should focus on the ecological role of floating objects in biota dispersal and nutrient cycling.
Biological activity of photoproducts of merocyanine 540 generated by laser-light activation
NASA Astrophysics Data System (ADS)
Gulliya, Kirpal S.; Chanh, Tran C.; Pervaiz, Shazib; Harriman, Anthony; Matthews, James Lester
Controlled exposure of photoactive compounds to light prior to their use in biological targets results in the formation of heretofore unknown photoproducts. This process of photoproduct generation, termed "preactivation," renders the photactive compound capable of systemic use without further dependence on light. Preactivation of mercyanin 540 (MC540) and several other photoactive compounds is achievable by exposure to CW and pulse laser radiation. The singlet oxygen generated at excited states attacks the dye molucule itself, resulting in the formation of biologically active photoproducts. For preactivated MC540 (photoproducts of MC540) generated by exposure to argon laser light (514 nm) and light from free-electron laser, we have demonstrated its effectiveness in selective killing of certain types of cultured tumor cells as well as human immunodeficiency virus type 1 (HIV-1) with very low, if any, damage to normal cells and tisues. For example, approximately 90% of the Burkitt's lymphoma Daudi cells and HL-60 leukemic cells are killed by preactivated MC540 at a concentration of 120 ?g/ml. A two-hour treatment of cultured cells with buthionine sulfoxamine followed by the treatement with preactivated MC540 reults in 99.99% inhibition of clonogenic tumor stem cell growth. We also have demonstrated that preactivated MC540 is very effective in killing cell-free and cell-associated HIV-1. It also is very effective in killing HIV-1 and simian immunodeficiency virus (SIV) in virus-infected blood in vitro as determined by reverse transcriptase, P24, P17, core antigen expression and synctium formation. Treatment of HIV-1 with preactivated MC540 renders the treated HIV-1 incapable of binding to CD4 target molecules on T cells as determined by immunofluorescence and radioimmunoprecipitation assays. In vivo toxicology studies show that preactivated MC540 is very well tolerated and does not produce any signs of adverse reaction at the therapeutic doses, as determined by physical examination, serum eletrolyte measurements, blood chemistry, and histopathology. Photoproducts generated via the process of preactivation are currently under investigation for optimum activity and yield using high-peak, power-pulse lasers.
Stem cell activation by light guides plant organogenesis
Kuhlemeier, Cris
in the light, an effect that is mediated through the plant hormone cytokinin. Dark treatment also affects propose that cytokinin is required for meristem propagation, and that auxin redirects cytokinin environment controls the initiation of lateral organs by regulating two key hormones: auxin and cytokinin
Cerebral Vasomotion: A 0.1Hz Oscillation in Reflected Light Imaging of Neural Activity
John E. W. Mayhew; Stephen Askew; Ying Zheng; John Porrill; G. W. Max Westby; Peter Redgrave; David M. Rector; Ronald M. Harper
Imaging of scattered and reflected light from the surface of neural structures can reveal the functional architecture within large populations of neurons. These techniques exploit, as one of the principal signal sources, reflectance changes produced by local variation in blood volume and oxygen saturation related to neural activity. We found that a major source of variability in the captured light
Challenges for reducing the size of laser activated remote phosphor light engines for DLP projection
NASA Astrophysics Data System (ADS)
Hartwig, Ulrich; Bruemmer, Mathias
Laser activated remote phosphor (LARP) is an upcoming technology for high luminance SSL light engines. This presentation outlines some of the challenges met reducing the engine's size, so it can be retrofitted into DLP-projectors.
Time structure of locomotor activity in mice kept on different light���dark cycles
Bo Yang; Yanyou Liu; Yuhui Wang; Yueqi Wang; Yanyal Ling; Zhou Jiang; Zhengrong Wang; G. Cornelissen; F. Halberg
Objective. This study investigates how the shortening or lengthening of the circadian period of the environmental lighting schedule affects the circadian and extra-circadian structure of locomotor activity in mice, with particular focus on the circasemiseptan, circaseptan, and circadecadian components with anticipated periods of about 3.5, 7, and 10 days, respectively.Methods. The locomotor activity of mice kept on different light���dark (LD)
Lights, Camera, Action! Using Engaging Computer-Cued Activity Schedules.
ERIC Educational Resources Information Center
Kimball, Jonathan W.; Kinney, Elisabeth M.; Taylor, Bridget A.; Stromer, Robert
This article discusses using individualized multimedia activity schedules as a technology-based instruction for young children with autism. The schedules serve as cues that can help students prepare for transitioning to between school activities. The benefits of using Microsoft PowerPoint in the classroom are described, along with implementation�
Relational Abstract Domains for the Detection of Floating-Point
Miné, Antoine
ESOP'2004 Relational Abstract Domains for the Detection of Floating-Point Run-Time Errors Antoine-time error. Floating-Point Nowadays, embedded software use floating-point numbers instead of fixed-point. Floating-point numbers are complex, not always understood by programmers. Floating-point numbers
Intel I/O, Floating point o DOS System Calls
Biagioni, Edoardo S.
Intel I/O, Floating point o DOS System Calls o Floating point 2 #12; Floating Point o integer: 1, 2, 3, 4 o fixed point: 100.001, 100.002, 123.456 o floating point: 100 x 103 , 101 x 103 , 123 x 105 o in the floating point
A novel light-dependent activation of DAGK and PKC in bovine photoreceptor nuclei.
Natalini, Paola M; Mateos, Melina V; Ilincheta de Boschero, M�nica G; Giusto, Norma M
In this work, we describe a selective light-dependent distribution of the lipid kinase 1,2-diacylglycerol kinase (EC 126.96.36.199, DAGK) and the phosphorylated protein kinase C alpha (pPKC?) in a nuclear fraction of photoreceptor cells from bovine retinas. A nuclear fraction enriched in small nuclei from photoreceptor cells (PNF), was obtained when a modified nuclear isolation protocol developed by our laboratory was used. We measured and compared DAGK activity as phosphatidic acid (PA) formation in PNF obtained from retinas exposed to light and in retinas kept in darkness using [?-(32)P]ATP or [(3)H]DAG. In the absence of exogenous substrates and detergents, no changes in DAGK activity were observed. However, when DAGK activity assays were performed in the presence of exogenous substrates, such as stearoyl arachidonoyl glycerol (SAG) or dioleoyl glycerol (DOG), and different detergents (used to make different DAGK isoforms evident), we observed significant light effects on DAGK activity, suggesting the presence of several DAGK isoforms in PNF. Under conditions favoring DAGK? activity (DOG, Triton X-100, dioleoyl phosphatidylserine and R59022) we observed an increase in PA formation in PNF from retinas exposed to light with respect to those exposed to darkness. In contrast, under conditions favoring DAGK? (SAG, octylglucoside and R59022) we observed a decrease in its activity. These results suggest different physiological roles of the above-mentioned DAGK isoforms. Western blot analysis showed that whereas light stimulation of bovine retinas increases DAGK? nuclear content, it decreases DAGK? and DAGK? content in PNF. The role of PIP2-phospholipase C in light-stimulated DAGK activity was demonstrated using U73122. Light was also observed to induce enhanced pPKC? content in PNF. The selective distribution of DAGK? and ? in PNF could be a light-dependent mechanism that in vertebrate retina promotes selective DAG removal and PKC regulation. PMID:24950064
The impact on seaplane floats during landing
NASA Technical Reports Server (NTRS)
Von Karman, TH
In order to make a stress analysis of seaplane floats, and especially of the members connecting the floats with the fuselage, it is of great importance to determine the maximum pressure acting on the floats during landing. Here, the author gives a formula for maximum pressures during landing that permits one to apply experimental results to different bodies and different velocities. The author notes that the formula checks very well with experimental results.
Tank Tests of Twin Seaplane Floats
NASA Technical Reports Server (NTRS)
Herrman, H; Kempf, G; Kloess, H
The following report contains the most essential data for the hydrodynamic portion of the twin-float problem. The following points were successfully investigated: 1) difference between stationary and nonstationary flow; 2) effect of the shape of the step; 3) effect of distance between floats; 4) effect of nose-heavy and tail-heavy moments; 5) effect of the shape of floats; 6) maneuverability.
Developing the ``Multiwavelength Astronomy: Galaxies in a Different Light'' Activity
NASA Astrophysics Data System (ADS)
Hemenway, M. K.; Jogee, S.; Fricke, K.; Worhatch, R.; Ruberg, L.
``Multiwavelength Astronomy'' is designed to lead high school students to understand astronomers' use of different wavelengths in studying the nature of galaxies. When developing the activity we followed the NASA-funded Virtual Design Center guidelines. With the project rationale and standards- alignment analysis completed, we surveyed high school students from several classes about their knowledge and interest in topics related to galaxy research. Their responses, and later pilot tests with secondary teachers and students, informed the development team's efforts. Topics included are the electromagnetic spectrum, false-color imaging, image resolution, Wien's law, and galaxy morphology. These were chosen to serve as prerequisites for future computer-intensive activities, which would involve students with data sets from the HST GEMS survey, one of the widest-area galaxy surveys conducted in two filters to date. Our description of the development process illustrates how we integrated topics of student interest into the activity while adhering to the design goal of incrementally augmenting student conceptual learning through a series of successive activities. Products for this activity include student and teacher guides, series of galaxy images in different wavelengths, a PowerPoint presentation, and sample materials for student assessment and evaluation of the activities.
Remote control of molecular motors using light-activated gearshifting
NASA Astrophysics Data System (ADS)
Bryant, Zev
Engineering molecular motors with dynamically controllable properties will allow selective perturbation of mechanical processes in vivo and provide sophisticated components for directed nanoscale transport in vitro. We previously constructed myosin motors that respond to a change in [Ca++] by reversing their direction of motion along the polarized actin filament. To expand the potential applications of controllable molecular motors, we have now developed myosins that shift gears in response to blue light illumination. Light is a versatile control signal that can be readily modulated in time and space, and is generally orthogonal to cellular signaling. Using structure-guided protein engineering, we have incorporated LOV photoreceptor domains into the lever arms of chimeric myosins, resulting in motors that robustly speed up, slow down, or switch directions upon illumination. These genetically encoded motors should be directly deployable inside living cells. Our successful designs include constructs based on two different myosin classes, and we show that optical velocity control can be implemented in motors that move at microns/sec speeds, enabling practical biological and bioengineering applications.
Modeling International Space Station (ISS) Floating Potentials
NASA Technical Reports Server (NTRS)
Ferguson, Dale C.; Gardner, Barbara
The floating potential of the International Space Station (ISS) as a function of the electron current collection of its high voltage solar array panels is derived analytically. Based on Floating Potential Probe (FPP) measurements of the ISS potential and ambient plasma characteristics, it is shown that the ISS floating potential is a strong function of the electron temperature of the surrounding plasma. While the ISS floating potential has so far not attained the pre-flight predicted highly negative values, it is shown that for future mission builds, ISS must continue to provide two-fault tolerant arc-hazard protection for astronauts on EVA.
Tuning laccase catalytic activity with phosphate functionalized carbon dots by visible light.
Li, Hao; Guo, Sijie; Li, Chuanxi; Huang, Hui; Liu, Yang; Kang, Zhenhui
The phosphate functionalized carbon dots (PCDs) with high biocompatibility and low toxicity can be used as efficient additives for the construction of laccase/PCDs hybrids catalyst. A series of experiments indicated that the activity of laccase/PCDs was higher than that of free laccase (increased by 47.7%). When laccase/PCDs hybrids catalyst was irradiated with visible light (laccase/PCDs-Light), its activity was higher than that of laccase/PCDs hybrids without light irradiation (increased by 92.1%). In the present system, the T1 Cu in laccase was combined with the phosphate group on PCDs, which can increase binding capacity of laccase/PCDs hybrids and substrate. Further, the visible light irradiation increased the donating and accepting electronic capability of the laccase/PCDs hybrids, improving their catalytic activity. PMID:25886497
Activators of Peroxisome Proliferator-Activated Receptors Protect Human Skin from Ultraviolet-B-Light-Induced Inflammation
Stefan Kippenberger; Stefan Marcel Loitsch; Marcella Grundmann-Kollmann; Stephanie Simon; Tu-Anh Dang; Katja Hardt-Weinelt; Roland Kaufmann; August Bernd
Peroxisome proliferator-activated receptors (PPAR) are members of a nuclear receptor superfamily, which were initially described in the context of fatty acid degradation and adipocyte differentiation. In this study we tested the hypothesis that peroxisome proliferator-activated receptor activation also controls inflammation. In an in vitro model with human keratinocytes inflammation was mimicked by irradiation with ultraviolet B light (150 mJ per
Rapid prototyping of reflectors for vehicle lighting using laser activated remote phosphor
NASA Astrophysics Data System (ADS)
Lachmayer, Roland; Kloppenburg, Gerolf; Wolf, Alexander
Bright white light sources are of significant importance for automotive front lighting systems. Today's upper class vehicles mainly use HID or LED as light source. As a further step in this development laser diode based systems offer high luminance, efficiency and allow the realization of new styling concepts and new dynamic lighting functions. These white laser diode systems can either be realized by mixing different spectral sources or by combining diodes with specific phosphors. Based on the approach of generating light using a laser and remote phosphor, lighting modules are manufactured. Four blue laser diodes (450 nm) are used to activate a phosphor coating and thus to achieve white light. A segmented paraboloid reflector generates the desired light distribution for an additional car headlamp. We use high speed milling and selective laser melting to build the reflector system for this lighting module. We compare the spectral reflection grade of these materials. Furthermore the generated modules are analyzed regarding their efficiency and light distribution. The use of Rapid Prototyping technologies allows an early validation of the chosen concept and is supposed to reduce cost and time in the product development process significantly. Therefor we discuss costs and times of the applied manufacturing technologies.
33 CFR 143.120 - Floating OCS facilities.
Code of Federal Regulations, 2012 CFR
...2012-07-01 2012-07-01 false Floating OCS facilities. 143.120 Section...EQUIPMENT OCS Facilities � 143.120 Floating OCS facilities. (a) Before construction is started on a proposed floating OCS facility, the owner...
33 CFR 143.120 - Floating OCS facilities.
Code of Federal Regulations, 2013 CFR
...2013-07-01 2013-07-01 false Floating OCS facilities. 143.120 Section...EQUIPMENT OCS Facilities � 143.120 Floating OCS facilities. (a) Before construction is started on a proposed floating OCS facility, the owner...
33 CFR 143.120 - Floating OCS facilities.
Code of Federal Regulations, 2014 CFR
...2014-07-01 2014-07-01 false Floating OCS facilities. 143.120 Section...EQUIPMENT OCS Facilities � 143.120 Floating OCS facilities. (a) Before construction is started on a proposed floating OCS facility, the owner...
33 CFR 143.120 - Floating OCS facilities.
Code of Federal Regulations, 2011 CFR
...2011-07-01 2011-07-01 false Floating OCS facilities. 143.120 Section...EQUIPMENT OCS Facilities � 143.120 Floating OCS facilities. (a) Before construction is started on a proposed floating OCS facility, the owner...
33 CFR 143.120 - Floating OCS facilities.
Code of Federal Regulations, 2010 CFR
...2010-07-01 2010-07-01 false Floating OCS facilities. 143.120 Section...EQUIPMENT OCS Facilities � 143.120 Floating OCS facilities. (a) Before construction is started on a proposed floating OCS facility, the owner...
14 CFR 23.535 - Auxiliary float loads.
Code of Federal Regulations, 2010 CFR
...2010-01-01 2010-01-01 false Auxiliary float loads. 23.535 Section 23.535 Aeronautics...COMMUTER CATEGORY AIRPLANES Structure Water Loads � 23.535 Auxiliary float loads. (a) General. Auxiliary floats...
14 CFR 25.535 - Auxiliary float loads.
Code of Federal Regulations, 2010 CFR
...2010-01-01 2010-01-01 false Auxiliary float loads. 25.535 Section 25.535 Aeronautics...TRANSPORT CATEGORY AIRPLANES Structure Water Loads � 25.535 Auxiliary float loads. (a) General. Auxiliary floats...
14 CFR 25.535 - Auxiliary float loads.
Code of Federal Regulations, 2012 CFR
...2012-01-01 2012-01-01 false Auxiliary float loads. 25.535 Section 25.535 Aeronautics...TRANSPORT CATEGORY AIRPLANES Structure Water Loads � 25.535 Auxiliary float loads. (a) General. Auxiliary floats...
14 CFR 23.535 - Auxiliary float loads.
Code of Federal Regulations, 2012 CFR
...2012-01-01 2012-01-01 false Auxiliary float loads. 23.535 Section 23.535 Aeronautics...COMMUTER CATEGORY AIRPLANES Structure Water Loads � 23.535 Auxiliary float loads. (a) General. Auxiliary floats...
14 CFR 23.535 - Auxiliary float loads.
Code of Federal Regulations, 2014 CFR
...2014-01-01 2014-01-01 false Auxiliary float loads. 23.535 Section 23.535 Aeronautics...COMMUTER CATEGORY AIRPLANES Structure Water Loads � 23.535 Auxiliary float loads. (a) General. Auxiliary floats...
14 CFR 23.535 - Auxiliary float loads.
Code of Federal Regulations, 2013 CFR
...2013-01-01 2013-01-01 false Auxiliary float loads. 23.535 Section 23.535 Aeronautics...COMMUTER CATEGORY AIRPLANES Structure Water Loads � 23.535 Auxiliary float loads. (a) General. Auxiliary floats...
14 CFR 25.535 - Auxiliary float loads.
Code of Federal Regulations, 2014 CFR
...2014-01-01 2014-01-01 false Auxiliary float loads. 25.535 Section 25.535 Aeronautics...TRANSPORT CATEGORY AIRPLANES Structure Water Loads � 25.535 Auxiliary float loads. (a) General. Auxiliary floats...
14 CFR 23.535 - Auxiliary float loads.
Code of Federal Regulations, 2011 CFR
...2011-01-01 2011-01-01 false Auxiliary float loads. 23.535 Section 23.535 Aeronautics...COMMUTER CATEGORY AIRPLANES Structure Water Loads � 23.535 Auxiliary float loads. (a) General. Auxiliary floats...
14 CFR 25.535 - Auxiliary float loads.
Code of Federal Regulations, 2013 CFR
...2013-01-01 2013-01-01 false Auxiliary float loads. 25.535 Section 25.535 Aeronautics...TRANSPORT CATEGORY AIRPLANES Structure Water Loads � 25.535 Auxiliary float loads. (a) General. Auxiliary floats...
14 CFR 25.535 - Auxiliary float loads.
Code of Federal Regulations, 2011 CFR
...2011-01-01 2011-01-01 false Auxiliary float loads. 25.535 Section 25.535 Aeronautics...TRANSPORT CATEGORY AIRPLANES Structure Water Loads � 25.535 Auxiliary float loads. (a) General. Auxiliary floats...
Smooth Planning for Free-floating Space Robots Using Polynomials *
Papadopoulos, Evangelos
Smooth Planning for Free-floating Space Robots Using Polynomials * Evangelos Papadopoulos, Ioannis) is acknowledged. Abstract Free-floating space manipulator systems, have spacecraft actuators turned off free�floating space manipulator systems is developed that allows simultaneous manipulator end
Coupled Dynamic Analysis of Multiple Unit Floating Offshore Wind Turbine
Bae, Yoon Hyeok
floating wind turbines, so the effects of such high-frequency excitations from the tower and blades need to be checked. 5 Another concept for floating offshore wind farms is the Multiple Unit Floating Offshore Wind Turbine (MUFOWT). This model...
Orexinergic signaling mediates light-induced neuronal activation in the dorsal raphe nucleus
Adidharma, Widya; Leach, Greg; Yan, Lily
Seasonal affective disorder (SAD), a major depressive disorder recurring in the fall and winter, is caused by the reduction of light in the environment, and its depressive symptoms can be alleviated by bright light therapy. Both circadian and monoaminergic systems have been implicated in the etiology of SAD. However, the underlying neural pathways through which light regulates mood are not well understood. The present study utilized a diurnal rodent model, Arvicanthis niloticus, to explore the neural pathways mediating the effects of light on brain regions involved in mood regulation. Animals kept in constant darkness received light exposure in early subjective day, the time when light therapy is usually applied. The time course of neural activity following light exposure was assessed using Fos as a marker in the following brain regions/cells: the suprachiasmatic nucleus (SCN), orexin neurons in the perifornical-lateral hypothalamic area (PF-LHA) and the dorsal raphe nucleus (DRN). A light-induced increase in Fos expression was observed in orexin neurons and the DRN, but not in the SCN. As the DRN is densely innervated by orexinergic inputs, the involvement of orexinergic signaling in mediating the effects of light on the DRN was tested in the second experiment. The animals were injected with the selective orexin receptor type 1 (OXR1) antagonist SB-334867 prior to the light exposure. The treatment of SB-334867 significantly inhibited the Fos induction in the DRN. The results collectively point to the role of orexin neurons in mediating the effects of light on the mood-regulating monoaminergic areas, suggesting an orexinergic pathway that underlies light-dependent mood fluctuation and the beneficial effects of light therapy. PMID:22710065
Reversible Light-Activation of Ribulose Bisphosphate Carboxylase/Oxygenase in Isolated Barley Protoplasts and Chloroplasts
Sicher, Richard C.
The enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase displayed near-maximal activity in isolated, intact barley (Hordeum vulgare L. cv. Pennrad) mesophyll protoplasts. The carboxylase deactivated 40 to 50% in situ when protoplasts were dark-incubated 20 minutes in air-equilibrated solutions. Enzyme activity was fully restored after 1 to 2 minutes of light. Addition of 5 millimolar NaHCO3 to the incubation medium prevented dark-inactivation of the carboxylase. There was no permanent CO2-dependent activation of the protoplast carboxylase either in light or dark. Activation of the carboxylase from ruptured protoplasts was not increased significantly by in vitro preincubation with CO2 and Mg2+. In contrast to the enzyme in protoplasts, the carboxylase in intact barley chloroplasts was not fully reactivated by light at atmospheric CO2 levels. The lag phase in carbon assimilation was not lengthened by dark-adapting protoplasts to low CO2 demonstrating that light-activation of the carboxylase was not involved in photosynthetic induction. Irradiance response curves for reactivation of the the carboxylase and for CO2 fixation by isolated barley protoplasts were similar. The above results show that there was a fully reversible light-activation of the carboxylase in isolated barley protoplasts at physiologically significant CO2 levels. PMID:16662497
Activation of sperm EGFR by light irradiation is mediated by reactive oxygen species.
Shahar, Shiran; Hillman, Pnina; Lubart, Rachel; Ickowicz, Debby; Breitbart, Haim
To acquire fertilization competence, spermatozoa must undergo several biochemical and motility changes in the female reproductive tract, collectively called capacitation. Actin polymerization and the development of hyperactivated motility (HAM) are part of the capacitation process. In a recent study, we showed that irradiation of human sperm with visible light stimulates HAM through a mechanism involving reactive-oxygen-species (ROS), Ca(2+) influx, protein kinases A (PKA), and sarcoma protein kinase (Src). Here, we showed that this effect of light on HAM is mediated by ROS-dependent activation of the epidermal growth factor receptor (EGFR). Interestingly, ROS-mediated HAM even when the EGFR was activated by EGF, the physiological ligand of EGFR. Light irradiation stimulated ROS-dependent actin polymerization, and this effect was abrogated by PBP10, a peptide which activates the actin-severing protein, gelsolin, and causes actin-depolymerization in human sperm. Light-stimulated tyrosine phosphorylation of Src-dependent gelsolin, resulting in enhanced HAM. Thus, light irradiation stimulates HAM through a mechanism involving Src-mediated actin polymerization. Light-stimulated HAM and in vitro-fertilization (IVF) rate in mouse sperm, and these effects were mediated by ROS and EGFR. In conclusion, we show here that irradiation of sperm with visible light, enhances their fertilization capacity via a mechanism requiring ROS, EGFR and HAM. PMID:24724551
Effects of oxygen on light activation in covalent adaptable network polymers.
Zhao, Zeang; Mu, Xiaoming; Sowan, Nancy; Pei, Yongmao; Bowman, Christopher N; Jerry Qi, H; Fang, Daining
Light activated polymers are a novel group of active materials that deform when irradiated with light at specific wavelengths. This paper focuses on the understanding and evaluation of light activated covalent adaptable networks formed by radical polymerization reactions, which have potential applications as novel actuators, surface patterning, and light-induced bending and folding. In these polymer networks, free radicals are generated upon light irradiation and lead to evolution of the polymer network structure through bond exchange reactions. It is well known that oxygen is an important inhibitor in radical-based chemistry as oxygen reacts with free radicals and renders them as inactive species towards further propagation and reaction. However, it is unclear how radical depletion by oxygen may affect the light-induced actuation. This paper studies the effects of oxygen on both stress relaxation and bending actuation. Light induced stress relaxation experiments are conducted in an environmental chamber where the concentration of oxygen is controlled by the nitrogen flow. A constitutive model that considers oxygen diffusion, radical termination due to oxygen, and the polymer network evolution is developed and used to study the stress relaxation and bending, and the model predictions agree well with experiments. Parametric studies are conducted to identify the situations where the effects of oxygen are negligible and other conditions where they must be considered. PMID:26138805
The Light Wavelength Affects the Ontogeny of Clock Gene Expression and Activity Rhythms in Zebrafish Larvae
Di Rosa, Viviana; Frigato, Elena; L�pez-Olmeda, Jos� F.; S�nchez-V�zquez, Francisco J.; Bertolucci, Cristiano
Light plays a key role in synchronizing rhythms and setting the phase of early development. However, to date, little is known about the impact of light wavelengths during the ontogeny of the molecular clock and the behavioural rhythmicity. The aim of this research was to determine the effect of light of different wavelengths (white, blue and red) on the onset of locomotor activity and clock gene (per1b, per2, clock1, bmal1 and dbp) expression rhythms. For this purpose, 4 groups of zebrafish embryo/larvae were raised from 0 to 7 days post-fertilization (dpf) under the following lighting conditions: three groups maintained under light:dark (LD) cycles with white (full visible spectrum, LDW), blue (LDB), or red light (LDR), and one group raised under constant darkness (DD). The results showed that lighting conditions influenced activity rhythms. Larvae were arrhythmic under DD, while under LD cycles they developed wavelength-dependent daily activity rhythms which appeared earlier under LDB (4 dpf) than under LDW or LDR (5 dpf). The results also revealed that development and lighting conditions influenced clock gene expression. While clock1 rhythmic expression appeared in all lighting conditions at 7 dpf, per1b, per2 and dbp showed daily variations already at 3 dpf. Curiously, bmal1 showed consistent rhythmic expression from embryonic stage (0 dpf). Summarizing, the data revealed that daily rhythms appeared earlier in the larvae reared under LDB than in those reared under LDW and LDR. These results emphasize the importance of lighting conditions and wavelengths during early development for the ontogeny of daily rhythms of gene expression and how these rhythms are reflected on the behavioural rhythmicity of zebrafish larvae. PMID:26147202
A Classroom Demonstration of Rayleigh Light Scattering in Optically Active and Inactive Systems.
ERIC Educational Resources Information Center
Pecina, Monica Avalos; Smith, Charles A.
Argues that the concept of optical activity is vague to students because it is difficult for instructors to demonstrate the phenomenon in the classroom. Presents a demonstration that allows students to observe and manipulate the optical path of polarized light through optically inactive and active solutions. (CCM)
Effects of temperature and photosynthetic inhibitors on light activation of C4-phosphoenolpyruvate carboxylase
Y. Samaras; Y. Manetas; N. A. Gavalas
Phosphoenolpyruvate carboxylase from leaves of the C4 plant Setaria verticillata (L.) Beauv. is activated by light; day levels of activity are reached after 30 minutes of illumination. Photoactivation is prevented by inhibitors of photosynthetic electron flow or of photophosphorylation and by D,L-glyceraldehyde, which inhibits the reductive pentose phosphate pathway.
Lights, Camera, Action!: A Language Arts Activity for Middle School Students.
ERIC Educational Resources Information Center
Ikan, Patricia A.; Conderman, Gregory
"Lights, Camera, Action" is a culminating language arts video activity for middle school students with mild disabilities, designed to integrate reading, writing, listening, speaking, acting, drawing, technical, and time-management skills. The cooperative learning activity resulted in production of a short videotaped program which was later viewed�
Light stimulates tyrosine hydroxylase activity and dopamine synthesis in retinal amacrine neurons.
Iuvone, P M; Galli, C L; Garrison-Gund, C K; Neff, N H
Retinal dopamine-containing amacrine neurons are rapidly activated by light, as shown by an increase in the rate of dopamine formation in vivo and a concomitant increase in the activity of tyrosine hydroxylase, measured in vitro with a subsaturating concentration of pteridine cofactor. Activation of tyrosine hydroxylase also occurs when isolated eyes from rats killed in the dark are exposed to a strobe light. Studies of amacrine neurons should provide basic data about the biochemical processing of visual information, as well as the physiological presynaptic regulatory mechanisms of dopamine-containing neurons. PMID:30997
Floating patella associated with lymphoedema
Vun, Shen Hwa; Bayam, Levent; Drampalos, Efstathios; Jesry, Mohammed; Fadel, George
Ipsilateral injury of more than one component of the knee extensor apparatus is rare. It is mostly associated with previous trauma, surgery, immunosuppression therapy and systemic disease. We present the first documented case of a spontaneous bifocal disruption of the knee extensor apparatus (i.e. floating patella) associated with lymphoedema. This case highlights the importance of considering lymphoedema as another risk factor for rupture of the knee extensor apparatus. It also highlights the importance of assessing all components of the knee extensor apparatus in patients presenting with acute knee injuries. PMID:25802253
Effects of special blue fluorescent light on hepatic mixed-function oxidase activity in the rat
Davis, D.R.; Yeary, R.A.; Randall, G.
Phototherapy has been widely used in the treatment of neonatal hyperbilirubinemia. Recent reports, however, have indicated that fluorescent light may be toxic and mutagenic to mammalian cells. these findings suggest possible long-term side effects with the use of phototherapy. This study was undertaken to determine the effects of phototherapy on hepatic microsomal enzyme activity. The exposure of Sprague-Dawley and Gunn rats to special blue fluorescent light at an average irradiance of 1,200 microW/cm2 resulted in no significant changes in liver microsomal enzyme activity for aniline hydroxylase, p-nitroanisole-O-demethylase, ethylmorphine-N-demethylase, cytochrome c reductase or the quantity of cytochrome P-450. A significant decrease in aniline hydroxylase and p-nitroanisole-O-demethylase activity was observed when liver microsomes were exposed in vitro to special blue fluorescent light. Photoactivated bilirubin did not effect the activity of the mixed-function oxidase enzymes measured under the conditions of this study.
Sinking and Floating: A Graphical Representation of the Concept of Density
NSDL National Science Digital Library
Gregory Benedis-Grab
Density is a derived quantity that can be confusing for middle school students. Try using a graphical depiction of mass and volume to guide students in understanding and applying this concept. In this activity, students will collect various materials, test whether each of the objects will float or sink in tap water, and measure the volume and mass of each object. By graphing the data, students will make the important conceptual leap from their initial thoughts and findings to exact criteria for floating.
Control of Thermocapillary Convection and Homogeneity of Floating-Zone Grown Crystals by Vibration
Xuefeng Shen
In this novel study, the controlled surface streaming flow (CSSF) was generated by end-wall vibration and applied to offset TC flow in a float-zone. Evidence gathered through flow visualization, temperature measurements, and observation of a flat solid-liquid interface proved the validity of controlling thermocapillary convection in the float-zone by this active-flow-balancing technique. In our experimental range, the streaming velocity (U)
Future float zone development in industry
NASA Technical Reports Server (NTRS)
Sandfort, R. M.
The present industrial requirements for float zone silicon are summarized. Developments desired by the industry in the future are reported. The five most significant problems faced today by the float zone crystal growth method in industry are discussed. They are economic, large diameter, resistivity uniformity, control of carbon, and swirl defects.
Algorithms for arbitrary precision floating point arithmetic
Douglas M. Priest
The author presents techniques for performing computations of very high accuracy using only straightforward floating-point arithmetic operations of limited precision. The validity of these techniques is proved under very general hypotheses satisfied by most implementations of floating-point arithmetic. To illustrate the applications of these techniques, an algorithm is presented which computes the intersection of a line and a line segment.
Floating Entanglement Witness Measure and Genetic Algorithm
A. Baghbanpourasl; G. Najarbashi; M. Seyedkazemi
In this paper based on the notion of entanglement witness, a new measure of entanglement called floating entanglement witness measure is introduced which satisfies some of the usual properties of a good entanglement measure. By exploiting genetic algorithm, we introduce a classical algorithm that computes floating entanglement witness measure. This algorithm also provides a method for finding entanglement witness for a given entangled state.
Towards sensible floating-point arithmetic
Cody, W.J.
Efforts to promote the development of high-quality transportable numerical software show that few, if any, of the floating-point arithmetic systems in existing computers are completely satisfactory for serious numerical computation. Examination of the defects in these systems leads to specifications for a sensible floating-point system from a numerical analyst's viewpoint. 1 table.
Circadian rhythm in pineal N-acetyltransferase activity: phase shifting by light pulses (I).
Binkley, S; Muller, G; Hernandez, T
N-Acetyltransferase activity (NAT) in the pineal gland has a circadian rhythm which is responsive to environmental light-dark cycles. The rhythm entrains to (synchronizes with or is phased by) light-dark cycles. To assess the means by which phase resetting is accomplished, the phase response of the pineal NAT rhythm to light pulses was examined using chicks (Gallus domesticus). When 4-h light pulses were imposed on chicks at intervals over a 24-h period of darkness and the time of the next rise in NAT was determined in darkness, it was found that: (1) pulses early in the subjective dark time delayed the rise in NAT, (2) pulses late in the subjective dark time advanced the rise in NAT, and (3) pulses in the subjective light time were relatively ineffective. These results are typical of a circadian phase response curve and show that an enzyme with a circadian rhythm is similar to other circadian rhythms studied. PMID:7276958
Activity rhythms in house sparrows exposed to natural lighting for one year
Sue Binkley; Karen Mosher
Perching activity was recorded in house sparrows (Passer domesticus) exposed to natural light for one year. As expected, the sparrows� activity duration shortened to 9.6 hours in December when the days were 9.35 hours long; and the sparrows� activity duration lengthened to 15 hours in June when the days were 15.02 hours long. In addition to this large and expected
Staphylococcus aureus small colony variants are susceptible to light activated antimicrobial agents
Background Antibiotic therapy can select for small colony variants of Staphylococcus aureus that are more resistant to antibiotics and can result in persistent infections, necessitating the development of more effective antimicrobial strategies to combat small colony variant infections. Photodynamic therapy is an alternative treatment approach which utilises light in combination with a light-activated antimicrobial agent to kill bacteria via a non-specific mechanism of action. In this study, we investigated whether the combination of 665�nm laser light and the light-activated antimicrobial agent methylene blue was able to successfully kill S. aureus small colony variants. S. aureus and isogenic stable small colony variant were exposed to varying doses (1.93 to 9.65�J/cm2) of 665�nm laser light in the presence of varying concentrations (1 to 20�?M) of methylene blue. Results The combination of 665�nm laser light and methylene blue was found to be an effective strategy for the killing of small colony variants. At the highest light dose (9.65�J/cm2) and methylene blue concentration (20�?M) tested, the number of viable bacteria decreased by approximately 6.9 log10 for the wild type and approximately 5 log10 for the small colony variant. Conclusions These results suggest that photodynamic therapy has potential for use in the treatment of superficial infections caused by small colony variants of S. aureus and supports further research in this field. PMID:24010944
Control of Protein Activity and Cell Fate Specification via Light-Mediated Nuclear Translocation
Zimmerman, Seth P.; Bear, James E.; Goldstein, Bob; Hahn, Klaus; Kuhlman, Brian
Light-activatable proteins allow precise spatial and temporal control of biological processes in living cells and animals. Several approaches have been developed for controlling protein localization with light, including the conditional inhibition of a nuclear localization signal (NLS) with the Light Oxygen Voltage (AsLOV2) domain of phototropin 1 from Avena sativa. In the dark, the switch adopts a closed conformation that sterically blocks the NLS motif. Upon activation with blue light the C-terminus of the protein unfolds, freeing the NLS to direct the protein to the nucleus. A previous study showed that this approach can be used to control the localization and activity of proteins in mammalian tissue culture cells. Here, we extend this result by characterizing the binding properties of a LOV/NLS switch and demonstrating that it can be used to control gene transcription in yeast. Additionally, we show that the switch, referred to as LANS (light-activated nuclear shuttle), functions in the C. elegans embryo and allows for control of nuclear localization in individual cells. By inserting LANS into the C. elegans lin-1 locus using Cas9-triggered homologous recombination, we demonstrated control of cell fate via light-dependent manipulation of a native transcription factor. We conclude that LANS can be a valuable experimental method for spatial and temporal control of nuclear localization in vivo. PMID:26083500
Investigation of tunable LED lighting for general illumination employing preliminary activity recognition sensor network
NASA Astrophysics Data System (ADS)
Thompson, Maria; Spaulding, Jeremy; Larson, Kent; Hall, Harrison
Digitally controlled solid state lighting systems can afford a range of different qualities of light, adjustable to users' requirements. Sensor networks allow lighting changes to be actuated in response to the location, activities, and paths of the occupants. This paper reports initial results of an ongoing research to explore strategic control of a tunable LED system, in response to a preliminary activity recognition platform, as well as the associated human factors. Tunable LED panels connected to a sensor network were installed to illuminate three distinct occupied spaces: a private office, a public office space and a corridor at MIT Media Lab. Human factors experiments were conducted to assess visual acceptability under changing lighting conditions. In the first phase variations in color rendering were applied to verify perception of subtle changes in white lighting. Results from this phase indicate that it is possible to correlate activities with sensitivity to spectral change. In the second phase the question is how colored light can be used for energy savings and as a communication medium in these commercial spaces.
Red Light Regulates Calcium-Activated Potassium Channels in Mougeotia Plasma Membrane 1
Lew, Roger R.; Serlin, Bruce S.; Schauf, Charles L.; Stockton, Marsha E.
The alga Mougeotia has a large central chloroplast whose positioning is regulated by photoactivation of phytochrome, possibly via modulation of cytosolic calcium (Serlin B, Roux SJ [1984] Proc Natl Acad Sci USA 81: 6368-6372). We used the patch clamp technique to examine the effects of red and far-red light on ion channel activity in the plasma membrane of Mougeotia protoplasts to determine if ion channels play a role in chloroplast movement. Patch clamping in the cell-attached mode reveals two channels of about 2 and 4 picoamperes amplitude at 0 millivolt (inside pipette) and estimated conductances of 30 and 65 picosiemens. They are activated by red light irradiation after a lag period of about 2 to 5 minutes. Far-red light, when applied immediately after red light irradiation, reverses this activation; otherwise it has no effect. This result implicates phytochrome. The addition of the calcium ionophore, A23187, also activates ion channel activity after a lag of a few minutes. The channels are not specific for calcium since they are present when calcium is removed from the external and pipette media. They are inhibited by quaternary ammonium ions. Thus, we believe they are calcium-activated potassium channels. Their possible role in chloroplast positioning is discussed. PMID:16667355
Regulation of ribulose bisphosphate carboxylase activity in vivo by a light-modulated inhibitor of catalysis
Seemann, Jeffrey R.; Berry, Joseph A.; Freas, Suzan M.; Krump, Martha A.
The activity of ribulose 1,5-bisphosphate carboxylase [RuBPCase; 3-phospho-D-glycerate carboxylyase (dimerizing), EC 126.96.36.199] in leaf extracts of a number of species kept in the dark overnight was found to be very low. This was not the result of a change in the activation state or in the amount of enzyme that could be extracted from �dark� leaves. Rather, in Phaseolus vulgaris it was due to an inhibitor of catalysis that occupied the catalytic site of the enzyme. This inhibitor was compartmentalized in the chloroplast and its maximum concentration in both dark leaves and in intact chloroplasts made from such leaves was slightly in excess of the RuBPCase catalytic site concentration. The inhibitor (a phosphate ester) was bound preferentially to the activated form of the enzyme, apparently functioning as a positive effector of activation. Treatment of the enzyme-inhibitor complex in vitro with alkaline phosphatase could restore RuBPCase activity. In vivo, both the initial rate of disappearance and the final concentration of inhibitor in intact leaves was found to vary with light intensity, and these changes could account for observed light-dependent changes in RuBPCase activity, indicating that light modulation of inhibitor concentration controlled RuBPCase activity. Recovery of activity in vivo could be inhibited by 3-(3?,4?,4-dichlorophenyl)-1,1-dimethylurea. PMID:16593629
Extended Onshore Control of a Floating Wind Turbine with Wave Disturbance Reduction
NASA Astrophysics Data System (ADS)
Christiansen, S.; Knudsen, T.; Bak, T.
Reaching for higher wind resources beyond the water depth limitations of monopile wind turbines, there has arisen the alternative of using floating wind turbines. But the response of wave induced loads significantly increases for floating wind turbines. Applying conventional onshore control strategies to floating wind turbines has been shown to impose negative damped oscillations in fore-aft due to the low natural frequency of the floating structure. Thus, we suggest a control loop extension of the onshore controller which stabilizes the system and reduces the wave disturbance. The results shows that when adding the suggested control loop with disturbance reduction to the system, improved performance is observed in power fluctuations, blade pitch activity, and platform oscillations.
Fos-tau-LacZ mice expose light-activated pathways in the visual system.
Greferath, Ursula; Nag, Nupur; Zele, Andrew J; Bui, Bang V; Wilson, Yvette; Vingrys, Algis J; Murphy, Mark
We have employed fos-tau-LacZ (FTL) transgenic mice to examine functional activation in the visual areas of the nervous system. The FTL mice express the marker gene lacZ in neurons and their processes following many different stimuli, and allow the imaging of activation from the level of the entire brain surface through individual neurons and their projections. Analysis of FTL expression in the retinas of mice following diurnal exposure to light shows that bipolar cells, specific classes of amacrine cells, ganglion cells, and a dense network of processes in the inner plexiform layer are functionally activated. In animals deprived of light, there is almost no activity in the retina. In the lateral geniculate nucleus (LGN), light exposure appears responsible for FTL expression in dorsal nuclei, but not for expression in the ventral nuclei or the intergeniculate leaflet. In the superficial layers of the superior colliculus, FTL expression is highly dependent on light exposure. Similarly, light exposure is required for FTL expression in primary visual cortex (area 17), but some expression remains in area 18 of dark-adapted animals. Finally, using mice with one or both eyes missing, we have determined which parts of the visual system are dependent on the presence of a functional connectivity from the eye. These data demonstrate the usefulness of the FTL mice to map functional activation within the entire visual system. Furthermore, we can capture visual activation in a conscious animal. Our findings give an insight into the architecture of activity within the retina and throughout the visual system. PMID:15528103
NSLS 2007 Activity Report (National Synchrotron Light Source Activity Report 2007)
Miller ,L.; Nasta, K.
The National Synchrotron Light Source is one of the world's most productive and cost-effective user facilities. With 2,219 individual users, about 100 more than last year, and a record-high 985 publications, 2007 was no exception. In addition to producing an impressive array of science highlights, which are included in this Activity Report, many NSLS users were honored this year for their scientific accomplishments. Throughout the year, there were major strides in the development of the scientific programs by strengthening strategic partnerships with major research resources and with the Center for Functional Nanomaterials (CFN). Of particular note, the Consortium for Materials Properties Research in Earth Sciences (COMPRES) received renewed funding for the next five years through the National Science Foundation. COMPRES operates four high-pressure NSLS beamlines--X17B2, X17B3, X17C, and U2A--and serves the earth science community as well as the rapidly expanding segment of researchers using high-pressure techniques in materials, chemical, and energy-related sciences. A joint appointment was made between the NSLS and Stony Brook University to further enhance interactions with COMPRES. There was major progress on two key beamline projects outlined in the Five-Year Strategic Plan: the X25 beamline upgrade and the construction of the X9 small angle scattering (SAXS) beamline. The X25 overhaul, which began with the installation of the in-vacuum mini-gap undulator (MGU) in January 2006, is now complete. X25 is once again the brightest beamline for macromolecular crystallography at the NSLS, and in tandem with the X29 undulator beamline, it will keep the NSLS at the cutting edge in this important area of research. Upgrade work associated with the new MGU and the front end for the X9 SAXS beamline--jointly developed by the NSLS and the CFN--also was completed. Beamline X9 will host the SAXS program that currently exists at beamline X21 and will provide new microbeam SAXS capabilities and much-needed beam time for the life sciences, soft condensed matter physics, and nanoscience communities. Looking toward the future, a significant step has been made in expanding the user base and diversifying the work force by holding the first Historically Black Colleges and Universities (HBCU) Professors' Workshop. The workshop, which brought 11 professors to the NSLS to learn how to become successful synchrotron users, concluded with the formation of an HBCU User Consortium. Finally, significant contributions were made in optics and detector development to enhance the utilization of the NSLS and address the challenges of NSLS-II. In particular, x-ray detectors developed by the NSLS Detector Section have been adopted by an increasing number of research programs both at the NSLS and at light sources around the world, speeding up measurement times by orders of magnitude and making completely new experiments feasible. Significant advances in focusing and high-energy resolution optics have also been made this year.
Supergravity Solutions from Floating Branes
Iosif Bena; Stefano Giusto; Clement Ruef; Nicholas P. Warner
We solve the equations of motion of five-dimensional ungauged supergravity coupled to three U(1) gauge fields using a floating-brane Ansatz in which the electric potentials are directly related to the gravitational warp factors. We find a new class of non-BPS solutions, that can be obtained linearly starting from an Euclidean four-dimensional Einstein-Maxwell base. This class - the largest known so far - reduces to the BPS and almost-BPS solutions in certain limits. We solve the equations explicitly when the base space is given by the Israel-Wilson metric, and obtain solutions describing non-BPS D6 and anti-D6 branes kept in equilibrium by flux. We also examine the action of spectral flow on solutions with an Israel-Wilson base and show that it relates these solutions to almost-BPS solutions with a Gibbons-Hawking base.
Alla Weinstein, Dominique Roddier, Kevin Banister
Principle Power Inc. and National Renewable Energy Lab (NREL) have completed a contract to assess the technical and economic feasibility of integrating wave energy converters into the WindFloat, resulting in a new concept called the WindWaveFloat (WWF). The concentration of several devices on one platform could offer a potential for both economic and operational advantages. Wind and wave energy converters can share the electrical cable and power transfer equipment to transport the electricity to shore. Access to multiple generation devices could be simplified, resulting in cost saving at the operational level. Overall capital costs may also be reduced, provided that the design of the foundation can be adapted to multiple devices with minimum modifications. Finally, the WindWaveFloat confers the ability to increase energy production from individual floating support structures, potentially leading to a reduction in levelized energy costs, an increase in the overall capacity factor, and greater stability of the electrical power delivered to the grid. The research conducted under this grant investigated the integration of several wave energy device types into the WindFloat platform. Several of the resulting system designs demonstrated technical feasibility, but the size and design constraints of the wave energy converters (technical and economic) make the WindWaveFloat concept economically unfeasible at this time. Not enough additional generation could be produced to make the additional expense associated with wave energy conversion integration into the WindFloat worthwhile.
A device to improve the SNR of the measurement of the positional floating reference point
NASA Astrophysics Data System (ADS)
Jiang, Jingying; Rong, Xuzheng; Zhang, Hao; Xu, Kexin
Previous studies have preliminarily validated the floating reference method and shown that it has the potential to improve the accuracy of non-invasive blood glucose sensing by Near-Infrared Spectroscopy. In order to make this method practical, it is necessary to precisely verify and measure the existence and variation features of the positional floating reference point. In this talk, a device which can precisely verify and measure the positional floating reference point is built. Since the light intensity of diffuse reflectance from the tested sample is very weak, a multipath detecting fibers system was built to improve signal-to-noise ratio. In this system, the fibers encircle the light source fiber which is regarded as the reference center of detecting fibers while they are moving. In addition, the position of each fiber is accurately controlled by manual translation stage to keep all detecting fibers always in the same radius around light source fiber. This ensures that received signal is coming from the same radial distance of light source. The variation of signal-to-noise ratio along with the different radial distance was investigated based on experiments. Results show that the application of this device could improve signal-to-noise ratio, and provide a new experimental method for the further study of positional floating reference point.
Effectiveness of Mechanical Aerationin Floating Aquatic Macrophyte-Based Wastewater Treatment Systems
Florida, University of
Effectiveness of Mechanical Aerationin Floating Aquatic Macrophyte-Based Wastewater Treatment to evaluate its effect on wastewater treatment effi- ciency andplantgrowth. Light aeration (0.003 and0.021Lnr2 tanks. Heavy aeration (1.03 and 3.53 L nr2 min-1 ) raised wastewater dissolved oxygen(DO) concentrations
46 CFR 180.137 - Stowage of life floats and buoyant apparatus.
Code of Federal Regulations, 2012 CFR
...be of a dark color or of a type certified to be resistant to deterioration from ultraviolet light; and (3) If metal, be corrosion resistant. (d) If the life float or buoyant apparatus does not have a painter attachment fitting, a...
46 CFR 180.137 - Stowage of life floats and buoyant apparatus.
Code of Federal Regulations, 2014 CFR
...be of a dark color or of a type certified to be resistant to deterioration from ultraviolet light; and (3) If metal, be corrosion resistant. (d) If the life float or buoyant apparatus does not have a painter attachment fitting, a...
46 CFR 180.137 - Stowage of life floats and buoyant apparatus.
Code of Federal Regulations, 2013 CFR
...be of a dark color or of a type certified to be resistant to deterioration from ultraviolet light; and (3) If metal, be corrosion resistant. (d) If the life float or buoyant apparatus does not have a painter attachment fitting, a...
46 CFR 180.137 - Stowage of life floats and buoyant apparatus.
Code of Federal Regulations, 2011 CFR
...be of a dark color or of a type certified to be resistant to deterioration from ultraviolet light; and (3) If metal, be corrosion resistant. (d) If the life float or buoyant apparatus does not have a painter attachment fitting, a...
46 CFR 180.137 - Stowage of life floats and buoyant apparatus.
Code of Federal Regulations, 2010 CFR
...be of a dark color or of a type certified to be resistant to deterioration from ultraviolet light; and (3) If metal, be corrosion resistant. (d) If the life float or buoyant apparatus does not have a painter attachment fitting, a...
Optics and Light Activities for Teachers of all Grade Levels from Easily Obtainable Supplies
NASA Astrophysics Data System (ADS)
Lindgren, Richard; Hendricks, Curtis; Lucatorto, Lynn; McNeilus, Thomas; Thornton, Stephen
Several hands-on activities in light and optics covering selected topics will be discussed in the context of home labs and how such activities can be incorporated into a distance-learning or online web-based course utilizing the latest communication technologies and the Internet. The presentation will focus on activities that can be constructed from easy to obtain supplies as well as a commercially available kit that we are having made available. Activities for teachers at the elementary level will focus on understanding light rays, shadows, and reflection from plane surfaces; at the middle school level will focus on curved mirrors and lenses, dispersion, and drawing ray diagrams; at the high school level will focus on Snell's law, the lens equation, wave interference, polarization, Young's experiment, and diffraction. A distance-learning, web-based course based on these home labs will be described. )
Program Converts VAX Floating-Point Data To UNIX
NASA Technical Reports Server (NTRS)
Alves, Marcos; Chapman, Bruce; Chu, Eugene
VAX Floating Point to Host Floating Point Conversion (VAXFC) software converts non-ASCII files to unformatted floating-point representation of UNIX machine. This is done by reading bytes bit by bit, converting them to floating-point numbers, then writing results to another file. Useful when data files created by VAX computer must be used on other machines. Written in C language.
Performance Boundaries of Massive Floating Car Data Offloading
Paris-Sud XI, Universit� de
Performance Boundaries of Massive Floating Car Data Offloading Silvia Ancona1,3 and Razvan Stanica1Politecnico di Bari, Bari, Italy Floating Car Data (FCD) consist of information generated by moving vehicles networks, floating car data, cellular uplink 1 Introduction The term Floating Car Data (FCD) defines
Maryland at College Park, University of
FLOATING GATE COMPARATOR WITH AUTOMATIC OFFSET MANIPULATION FUNCTIONALITY Eric Liu Wong, Pamela A nonvolatile floating gate charge storage for either offset nulling or au- tomatic programming of a desired is a constant value, it is natu- ral to store it using nonvolatile storage on a floating gate. Floating gate
Research on floating wind turbines: a literature survey
C. M. Wang; T. Utsunomiya; S. C. Wee; Y. S. Choo
This article presents a literature survey of research and development on floating wind turbines. The various, proposed conceptual designs for floating platforms used for floating wind turbines are described and the working principles of these various floater concepts are outlined. This is followed by an overview of the research work that has been undertaken pertaining to floating wind turbine technology
Photosynthetic activity and growth analysis of the plant {Costus spicatus} cultivated under different light conditions
NASA Astrophysics Data System (ADS)
Campos, V. M.; Pasin, L. A. A. P.; Barja, P. R.
The aim of the present work was to evaluate the effect of different radiance levels (25%, 50% and 100% of full sunlight) in growth (height, leaf area, number of leaves) and photosynthetic activity of the plant Costus spicatus, popularly known in Brazil as Caninha do Brejo. Photoacoustic (PA) measurements were performed in order to evaluate comparatively the photosynthetic activity rate of plants submitted to different light intensity regimes. The results obtained show that plants maintained under low light intensity levels (25% of sunlight) presented higher height, leaf area and number of leaves, while plants grown under full sunlight presented higher radicular length. PA measurements indicated higher photosynthetic rate for plants grown under 50% of full sunlight, but plants developed under 25% of full sunlight (75% shading) presented the fastest response to light incidence (photosynthetic induction).
Improved low-power semiconductor diode lasers for light activation of pharmaceutical agents
NASA Astrophysics Data System (ADS)
Lee, Susanne M.; Mueller, Eduard K.; Van de Workeen, Brian C.; Mueller, Otward M.
In photodynamic therapy, a photosensitizing dye is injected into the patient and the die accumulates in tumor tissue. The cancer cells are then destroyed by absorbing light of a specific wavelength, usually around 630 nm. One of the strong advantages of this therapy is that it destroys only malignant cells and causes less morbidity than standard treatments like surgery and radiotherapy. There are several other techniques that also utilize light activation of pharmaceutical agents in treatment of cancers such as breast cancer. One method of supplying this light activation is through the use of diode lasers, which are constantly finding new application in all fields of medicine. However these lasers tend to be limited by their high cost per watt and multiple wavelength output. Cryogenically cooling such lasers provides higher power output and therefore longer device lifetime. We report quantification of these results from laser power meter and photospectrometer data.
High-contrast top-emitting organic light-emitting devices for active-matrix displays
Chih-Jen Yang; Chun-Liang Lin; Chung-Chih Wu; Yung-Hui Yeh; Chun-Cheng Cheng; Yen-Hsun Kuo; Tai-Hong Chen
Unlike previous high-contrast devices that all involve inserting extra layer(s) with optical purposes (e.g., absorption and interference) into the active region of devices, in this-letter we report a high-contrast top-emitting organic light-emitting device (OLED) that utilizes only optical characteristics of electrodes and anti-reflection coatings deposited outside the active region, thus reducing the complexity of devices. Furthermore, the device has an
Enhanced light microscopic visualization of oxidase activity with the cerium capture method
R. Gossrau; C. J. F. Noorden; W. M. Frederiks
Visualization methods for the light microscopic detection of the activity of oxidases after being localized with cerium ions as reported by Angerm�ller and Fahimi (1988a, b) are not suitable for the demonstration of H2O2-genrating oxidases at sites with low activity. Therefore, the cerium-diaminobenzidine (DAB) visualization procedure of these authors was modified. Nickel or cobalt ions were added to the DAB
The Effects of Computer-Aided Concept Cartoons and Outdoor Science Activities on Light Pollution
ERIC Educational Resources Information Center
Aydin, G�liz
The purpose of this study is to create an awareness of light pollution on seventh grade students via computer aided concept cartoon applications and outdoor science activities and to help them develop solutions; and to determine student opinions on the practices carried out. The study was carried out at a middle school in Mugla province of Aegean�
Modification of polycrystalline silicon as efficient anode for active-matrix organic light-emitting diodes
Modification of polycrystalline silicon as efficient anode for active- matrix organic light have proposed the use of polycrystalline silicon (p-Si) thin film as an alternative semitransparent, Clear Water Bay, Hong Kong Abstract The effects of different modification methods for polycrystalline
Vanadium pentoxide modified polycrystalline silicon anode for active-matrix organic light-emitting diodes
Vanadium pentoxide modified polycrystalline silicon anode for active-matrix organic light; published online 6 October 2005 Recently, polycrystalline silicon p-Si has been demonstrated because of its high conductivity and trans- parency. Recently, the use of polycrystalline silicon p
SCIENCE, OPTICS & YOU GUIDEBOOK m2: Light and LensesACTIVITY 4: EXPLORING WITH LENSES
Weston, Ken
SCIENCE, OPTICS & YOU GUIDEBOOK - 27 - m2: Light and LensesACTIVITY 4: EXPLORING WITH LENSES Module each of the lenses supplied in the Science, Optics and You package. Students will look at different AND LENSES MODULE m2 #12;SCIENCE, OPTICS & YOU GUIDEBOOK - 28 - #12;SCIENCE, OPTICS & YOU GUIDEBOOK - 29 - m2
Light and Heavy Heterosexual Activities of Young Canadian Adolescents: Normative Patterns and Differential Predictors
ERIC Educational Resources Information Center
Williams, Trish; Connolly, Jennifer; Cribbie, Robert
The objectives of this research were to explore patterns of heterosexual activity in early adolescence and to examine the differential pathways to light and heavy heterosexuality. We utilized the National Longitudinal Survey of Canadian Children and Youth (NLSCY) in which heterosexual behaviors, as well as puberty, parenting processes, peer�
Prolonged daily light exposure increases body fat mass through attenuation of brown adipose tissue activity.
Kooijman, Sander; van den Berg, Rosa; Ramkisoensing, Ashna; Boon, Mari�tte R; Kuipers, Eline N; Loef, Marieke; Zonneveld, Tom C M; Lucassen, Eliane A; Sips, Hetty C M; Chatzispyrou, Iliana A; Houtkooper, Riekelt H; Meijer, Johanna H; Coomans, Claudia P; Biermasz, Nienke R; Rensen, Patrick C N
Disruption of circadian rhythmicity is associated with obesity and related disorders, including type 2 diabetes and cardiovascular disease. Specifically, prolonged artificial light exposure associates with obesity in humans, although the underlying mechanism is unclear. Here, we report that increasing the daily hours of light exposure increases body adiposity through attenuation of brown adipose tissue (BAT) activity, a major contributor of energy expenditure. Mice exposed to a prolonged day length of 16- and 24-h light, compared with regular 12-h light, showed increased adiposity without affecting food intake or locomotor activity. Mechanistically, we demonstrated that prolonged day length decreases sympathetic input into BAT and reduces ?3-adrenergic intracellular signaling. Concomitantly, prolonging day length decreased the uptake of fatty acids from triglyceride-rich lipoproteins, as well as of glucose from plasma selectively by BAT. We conclude that impaired BAT activity is an important mediator in the association between disturbed circadian rhythm and adiposity, and anticipate that activation of BAT may overcome the adverse metabolic consequences of disturbed circadian rhythmicity. PMID:25964318
Optical chirality without optical activity: How surface plasmons give a twist to light
Aurelien Drezet; Cyriaque Genet; Jean-Yves Laluet; Thomas W. Ebbesen
Light interacts differently with left and right handed three dimensional chiral objects, like helices, and this leads to the phenomenon known as optical activity. Here, by applying a polarization tomography, we show experimentally, for the first time in the visible domain, that chirality has a different optical manifestation for twisted planar nanostructured metallic objects acting as isolated chiral metaobjects. Our
Inactivation of staphylococcal virulence factors using a light-activated antimicrobial agent
Sarah Tubby; Michael Wilson; Sean P Nair
BACKGROUND: One of the limitations of antibiotic therapy is that even after successful killing of the infecting microorganism, virulence factors may still be present and cause significant damage to the host. Light-activated antimicrobials show potential for the treatment of topical infections; therefore if these agents can also inactivate microbial virulence factors, this would represent an advantage over conventional antibiotic therapy.
Advanced polysilicon TFT technology for active matrix organic light-emitting diode displays
Miltiadis K. Hatalis; Mark J. Stewart; Robert S. Howell
This work discusses the features of a low temperature polysilicon thin film transistor (TFT) technology suitable for application in the new Active Matrix Organic Light Emitting Diode (AMOLED) displays. The most important facet of this work is the preparation of polysilicon films by the method of solid phase crystallization of amorphous silicon films using rapid thermal processing (RTP). It is
Audin, L. [Columbia Univ., New York, NY (United States)
EPAct covers a vast territory beyond lighting and, like all legislation, also contains numerous {open_quotes}favors,{close_quotes} compromises, and even some sleight-of-hand. Tucked away under Title XIX, for example, is an increase from 20% to 28% tax on gambling winnings, effective January 1, 1993 - apparently as a way to help pay for new spending listed elsewhere in the bill. Overall, it is a landmark piece of legislation, about a decade overdue. It remains to be seen how the Federal Government will enforce upgrading of state (or even their own) energy codes. There is no mention of funding for {open_quotes}energy police{close_quotes} in EPAct. Merely creating such a national standard, however, provides a target for those who sincerely wish to create an energy-efficient future.
Highly Active TiO2-Based Visible-Light Photocatalyst with Nonmetal Doping and Plasmonic Metal Decoration
Zhang, Qiao [University of California, Riverside; Lima, Diana Q. [University of California, Riverside; Chi, Miaofang [ORNL; Yin, Yadong [University of California, Riverside
A sandwich-structured photocatalyst shows an excellent performance in degradation reactions of a number of organic compounds under UV, visible light, and direct sunlight (see picture). The catalyst was synthesized by a combination of nonmetal doping and plasmonic metal decoration of TiO2 nanocrystals, which improves visible-light activity and enhances light harvesting and charge separation, respectively.
Study on the activation of styrene-based shape memory polymer by medium-infrared laser light
NASA Astrophysics Data System (ADS)
Leng, Jinsong; Zhang, Dawei; Liu, Yanju; Yu, Kai; Lan, Xin
This paper demonstrates the feasibility of shape memory polymer (SMP) activation by medium-infrared laser light. Medium-infrared light is transmitted by an optical fiber embedded in the SMP matrix, and the shape recovery process and temperature distribution are recorded by an infrared camera. Light-induced SMP exhibits potential applications in biomedicines and flexible displays.
Study on the activation of styrene-based shape memory polymer by medium-infrared laser light
Leng Jinsong; Yu Kai; Lan Xin [Center for Composite Materials and Structures, Harbin Institute of Technology, HeiLongJiang 150001 (China); Zhang Dawei [Center for Composite Materials and Structures, Harbin Institute of Technology, HeiLongJiang 150001 (China); Material Science and Engineering College, Northeast Forestry University, HeiLongJiang 150040 (China); Liu Yanju [Department of Astronautical Science and Mechanics, Harbin Institute of Technology, HeiLongJiang 150001 (China)
This paper demonstrates the feasibility of shape memory polymer (SMP) activation by medium-infrared laser light. Medium-infrared light is transmitted by an optical fiber embedded in the SMP matrix, and the shape recovery process and temperature distribution are recorded by an infrared camera. Light-induced SMP exhibits potential applications in biomedicines and flexible displays.
A floating-point technique for extending the available precision
T. J. Dekker
A technique is described for expressing multilength floating-point arithmetic in terms of singlelength floating point arithmetic, i.e. the arithmetic for an available (say: single or double precision) floating-point number system. The basic algorithms are exact addition and multiplication of two singlelength floating-point numbers, delivering the result as a doublelength floating-point number. A straight-forward application of the technique yields a set
Relative Dispersion of isobaric RAFOS Floats off Central California: Comparative Analysis of Estimation Techniques
NASA Astrophysics Data System (ADS)
Margolina, T.; Collins, C. A.; Ivanov, L. M.; Hsieh, C.
Dynamical regimes in the California Undercurrent and ocean interior off Central California are controlled by rich mesoscale activity, including eddies, filaments and turbulent jets. A unique dataset of 56 isobaric RAFOS floats was used to analyze relative dispersion in the region. The floats were launched in pairs and triads at 150- -600 m between 1993 and 2003 (http://www.oc.nps.navy.mil/npsRAFOS/). The launch design allowed us to identify about forty float pairs in several classes of initial separation distance. Taking into consideration the anisotropic nature of the California Undercurrent, alongshore and cross-shore separations were calculated for the identified pairs of float trajectories. We applied different techniques, both asymptotic and non-asymptotic, to estimate relative dispersion of the RAFOS floats. In addition to the probability distribution function of the mean square separation and its second- order moments, higher order moments were also considered to understand how much intermittency influence float dispersion. In addition to averaging distances at fixed times, two alternative approaches based on averaging times at fixed distance were tried, the finite size Lyapunov exponent and the parametrical exit time statistics. The latter was estimated both theoretically and using float sampling through the probability weighted moments. Statistical significance of the results as well as possible biases of the estimates due to horizontal and vertical shears were investigated. Different techniques give, in general, different dispersion regimes with power exponents varying between 0.5 and 2. Most differences occurred for the kurtosis and skewness at the initial stage for float pairs with small separation. The focus here was on finite sample size effects and an empirical criterion for evaluating the impact of sample size.
Verification of floating-point software
NASA Technical Reports Server (NTRS)
Hoover, Doug N.
Floating point computation presents a number of problems for formal verification. Should one treat the actual details of floating point operations, or accept them as imprecisely defined, or should one ignore round-off error altogether and behave as if floating point operations are perfectly accurate. There is the further problem that a numerical algorithm usually only approximately computes some mathematical function, and we often do not know just how good the approximation is, even in the absence of round-off error. ORA has developed a theory of asymptotic correctness which allows one to verify floating point software with a minimum entanglement in these problems. This theory and its implementation in the Ariel C verification system are described. The theory is illustrated using a simple program which finds a zero of a given function by bisection. This paper is presented in viewgraph form.
Notes 11. High pressure floating ring seals�
San Andres, Luis
Floating ring seals for compressors: leakage and force coefficients, seal lock up and effect on rotor stability, recommendations to reduce seal cross-coupled effects. Long oil seals as pressure barriers in industrial mixers: leakage and force...
Atraumatic floating clavicle and total claviculectomy.
Attarian, D E
We describe a patient with a floating clavicle of atraumatic origin treated by total claviculectomy. Clavicular function and anatomy are summarized relative to complete excision. Other treatment options for panclavicular instability are also discussed. PMID:12132804
Calcium activates the light-dependent conductance in melanopsin-expressing photoreceptors of amphioxus.
Peinado, Gabriel; Osorno, Tom�s; Gomez, Mar�a Del Pilar; Nasi, Enrico
Melanopsin, the photopigment of the "circadian" receptors that regulate the biological clock and the pupillary reflex in mammals, is homologous to invertebrate rhodopsins. Evidence supporting the involvement of phosphoinositides in light-signaling has been garnered, but the downstream effectors that control the light-dependent conductance remain unknown. Microvillar photoreceptors of the primitive chordate amphioxus also express melanopsin and transduce light via phospholipase-C, apparently not acting through diacylglycerol. We therefore examined the role of calcium in activating the photoconductance, using simultaneous, high time-resolution measurements of membrane current and Ca(2+) fluorescence. The light-induced calcium rise precedes the onset of the photocurrent, making it a candidate in the activation chain. Moreover, photolysis of caged Ca elicits an inward current of similar size, time course and pharmacology as the physiological photoresponse, but with a much shorter latency. Internally released calcium thus emerges as a key messenger to trigger the opening of light-dependent channels in melanopsin-expressing microvillar photoreceptors of early chordates. PMID:26056310
Strategies of making TiO2 and ZnO visible light active.
Rehman, Shama; Ullah, Ruh; Butt, A M; Gohar, N D
In modern purification techniques employing semiconductor mediated photooxidation of toxic substances, zinc oxide (ZnO) and titanium dioxide (TiO2) are the most widely used metal oxides due to their unique blend of properties. However, the band edges of these semiconductors lie in the UV region which makes them inactive under visible light irradiation. Researchers have been interested in the modification of electronic and optical properties of these metal oxides for their efficient use in water and air purification under visible light irradiation. Visible light activity has been induced in TiO2 and ZnO by surface modification via organic materials/semiconductor coupling and band gap modification by doping with metals and nonmetals, co-doping with nonmetals, creation of oxygen vacancies and oxygen sub-stoichiometry. This paper encompasses the progress and developments made so far through these techniques in the visible light photocatalysis with TiO2 and ZnO. Recently, nitrogen doping in titania has been extensively carried out and therefore somewhat detailed discussion in this respect has been presented. Visible light activation of titania clusters encapsulated in zeolite-Y by nitrogen doping and incorporation of dye or organic sensitizers inside the zeolite framework, has also been highlighted in this review. PMID:19540666
In 2005, the NSLS proved itself, once again, to be a center of scientific excellence. This remarkable facility, commissioned in the early 1980s, is still attracting some of the world's best researchers in almost every scientific field, who produce more than seven hundred scientific papers every year using the NSLS. The 'Science Highlights' and 'Feature Highlights' sections of this report are just a small sampling of the many, many impressive research projects conducted at the NSLS in 2005. For example, a user group synthesized and studied zinc-oxide nanowires, which have applications in many optical and electrical devices. Another user group studied how strontium and uranium are removed from high-level radioactive waste. And in another interesting study, users deciphered the basis for antibiotic resistance. However, as always, the success of these projects depends on the performance of the facility. Again this year, the rings were in top form--reliability was 96 percent for the x-ray ring and 99 percent for the VUV-IR ring. Additionally, to keep the NSLS as productive as possible and to continue to attract users, many beamline upgrade projects were completed this year. One of the highlights of these upgrades is the new mini-gap undulator installed at beamline X25. This insertion device is providing a much brighter x-ray source for the program at X25. In the always important area of safety, several noteworthy activities took place this year. In particular, NSLS staff made a major commitment to labeling and inspecting electrical equipment. And perhaps the best news is what didn't happen--there were no reportable occurrences related to environmental, safety, or health issues in 2005, and no injuries that resulted in restricted or lost time. We all owe thanks to the dedicated NSLS staff and users who have ensured that the NSLS remains a reliable, safe, up-to-date research facility. As 2005 came to an end, I stepped down as NSLS Chairman in order to focus my primary efforts on NSLS-II, the world-leading third-generation synchrotron planned for construction at BNL. NSLS-II passed a critical milestone in 2005 with the approval by the Department of Energy of CD-0. BNL has established the NSLS-II Project Organization within the Light Sources Directorate to put in place the management systems and infrastructure necessary to execute this complex undertaking. I will serve as NSLS-II Project Director and also retain my position as Associate Laboratory Director for Light Sources, with the NSLS reporting to me. Another exciting development is the planned establishment of the Joint Photon Sciences Institute (JPSI). JPSI will be devoted to cultivating and fostering collaborative, interdisciplinary R&D in areas of the physical sciences, engineering, and the life sciences that are united in employing synchrotron-based methods. JPSI will also develop new methods and applications that exploit the unique capabilities of NSLS-II and will serve as a gateway for NSLS-II users. JPSI will be a partnership between the Department of Energy and New York State, and I am delighted that New York State Governor George Pataki has pledged $30 million for the construction of the JPSI building. The building will be located adjacent to NSLS-II and will contain offices, meeting rooms, and specialized laboratories. The operating expenses of JPSI and funding for its research programs will be provided by the federal government. Until a permanent NSLS Director is selected, NSLS User Science Division Associate Chair Chi-Chang Kao will serve as the Interim NSLS Director. I couldn't be leaving the facility in more capable hands. Chi-Chang will lead NSLS staff and users this year in the development of a five-year strategic plan for the NSLS, scheduled for completion by the end of summer 2006. The plan will outline the course for the future operation and development of the NSLS, and will help ensure that the future of the NSLS remains as bright as its past.
Floating Ice-Algal Aggregates below Melting Arctic Sea Ice
Assmy, Philipp; Ehn, Jens K.; Fern�ndez-M�ndez, Mar; Hop, Haakon; Katlein, Christian; Sundfjord, Arild; Bluhm, Katrin; Daase, Malin; Engel, Anja; Fransson, Agneta; Granskog, Mats A.; Hudson, Stephen R.; Kristiansen, Svein; Nicolaus, Marcel; Peeken, Ilka; Renner, Angelika H. H.; Spreen, Gunnar; Tatarek, Agnieszka; Wiktor, Jozef
During two consecutive cruises to the Eastern Central Arctic in late summer 2012, we observed floating algal aggregates in the melt-water layer below and between melting ice floes of first-year pack ice. The macroscopic (1-15 cm in diameter) aggregates had a mucous consistency and were dominated by typical ice-associated pennate diatoms embedded within the mucous matrix. Aggregates maintained buoyancy and accumulated just above a strong pycnocline that separated meltwater and seawater layers. We were able, for the first time, to obtain quantitative abundance and biomass estimates of these aggregates. Although their biomass and production on a square metre basis was small compared to ice-algal blooms, the floating ice-algal aggregates supported high levels of biological activity on the scale of the individual aggregate. In addition they constituted a food source for the ice-associated fauna as revealed by pigments indicative of zooplankton grazing, high abundance of naked ciliates, and ice amphipods associated with them. During the Arctic melt season, these floating aggregates likely play an important ecological role in an otherwise impoverished near-surface sea ice environment. Our findings provide important observations and measurements of a unique aggregate-based habitat during the 2012 record sea ice minimum year. PMID:24204642
Travel Time Estimation Using Floating Car Data
Sevlian, Raffi
This report explores the use of machine learning techniques to accurately predict travel times in city streets and highways using floating car data (location information of user vehicles on a road network). The aim of this report is twofold, first we present a general architecture of solving this problem, then present and evaluate few techniques on real floating car data gathered over a month on a 5 Km highway in New Delhi.
Floating Bodies of Equilibrium. Explicit Solution
Franz Wegner
Explicit solutions of the two-dimensional floating body problem (bodies that can float in all positions) for relative density rho different from 1/2 and of the tire track problem (tire tracks of a bicycle, which do not allow to determine, which way the bicycle went) are given, which differ from circles. Starting point is the differential equation given in archive physics/0205059 and Studies in Appl. Math. 111 (2003) 167-183.
Decimal Floating-Point: Algorism for Computers
Michael F. Cowlishaw; Coventry CV
Decimal arithmetic is the norm in human calculations, and human-centric applications must use a decimal floating-point arithmetic to achieve the same results. Initial benchmarks indicate that some applications spend 50% to 90% of their time in decimal processing, because software decimal arithmetic suffers a 100� to 1000� performance penalty over hardware. The need for decimal floating-point in hardware is urgent.
Motion Projection for Floating Object Detection
Zhao-Yi Wei; Dah-jye Lee; David Jilk; Robert Schoenberger
Floating mines are a significant threat to the safety of ships in theatres of military or terrorist conflict. Automating mine\\u000a detection is difficult, due to the unpredictable environment and high requirements for robustness and accuracy. In this paper,\\u000a a floating mine detection algorithm using motion analysis methods is proposed. The algorithm aims to locate suspicious regions\\u000a in the scene using
Analysis of floating point operations in microcontrollers
Aswin Ramakrishnan; James M. Conrad
The purpose of this paper is to identify the advantages of including a floating point hardware \\/ a mathematical co-processor in microcontrollers used for critical floating point operations. Three different microcontrollers are considered: Renesas M16C\\/62P (CISC without FPU), ATMEGA1280 (RISC without MCU) and Renesas RX62N (CISC with FPU). Gauss-Seidel and Jacobi iterations for a system of 2 and 3 variables
Decimal Floating Point for future processors
Hossam A. H. Fahmy; Tarek ElDeeb; Mahmoud Yousef Hassan; Yasmin Farouk; R. R. Eissa
Many new designs for Decimal Floating Point (DFP) hardware units have been proposed in the last few years. To date, only the IBM POWER6 and POWER7 processors include internal units for decimal floating point processing. We have designed and tested several DFP units including an adder, multiplier, divider, square root, and fused-multiply-add compliant with the IEEE 754-2008 standard. This paper
Probability Analysis for CMOS Floating Gate Faults
Hua Xue; Chennian Di; Jochen A. G. Jess
The electrical behavior of a floating gate MOS transistor is mask-topology-dependent, i.e. floating on different sites of interconnection may result in different fault behavior. In this paper, we present a net-oriented deterministic approach to compute the probability of different open faults on each net, by taking into account the process defect statistics and mask layout data. The open faults causing
Synthesis of visible light active graphene-modified BaCrO4 nanocomposite photocatalyst
NASA Astrophysics Data System (ADS)
Gawande, Sandeep B.; Thakare, Sanjay R.
In situ chemical deposition sol-gel method has been used to prepare graphene oxide-BaCrO4 (GO-BaCrO4), which was then reduced to graphene-BaCrO4 (RGO-BaCrO4) under visible-light irradiation. X-ray diffraction, Fourier transform infrared spectroscopy, and transmission electron microscopy were used to study the morphological characteristics of the prepared composite material. This synthesis method offers effortless incorporation of a visible light active photocatalyst in a composite; the reduction of GO to RGO was carried out under visible light as well. Graphene sheets with high specific surface area and unique electronic properties can be used as a good support for BaCrO4 and enhance the photocatalytic activity for the degradation of methylene blue dye compared to pure BaCrO4. The poor photocatalytic activity of pure BaCrO4 is due to its fast charge recombination. Enhanced photocatalytic degradation activity is attributed predominantly to the presence of graphene, which serves as an electron collector and transporter to lengthen efficiently the lifetime of the photogenerated charge carriers from BaCrO4 nanoparticles. The modified surface of BaCrO4 acts as a good photocatalyst compared to unmodified BaCrO4. The optimum reaction time for synthesis and GO concentration in the composite to enhance photocatalytic activity are presented in this article.
Characterization of nucleoside triphosphatase activity in isolated pea nuclei and its photoreversible regulation by light
NASA Technical Reports Server (NTRS)
Chen, Y. R.; Roux, S. J.
A nucleoside triphosphatase (NTPase) present in highly purified preparations of pea nuclei was partially characterized. The activity of this enzyme was stimulated by divalent cations (Mg2+ = Mn2+ > Ca2+), but was not affected by the monovalent cations, Na+ and K+. The Mg(2+)-dependent activity was further stimulated by concentrations of Ca2+ in the low micromolar range. It could catalyze the hydrolysis of ATP, GTP, UTP, and CTP, all with a pH optimum of 7.5. The nuclear NTPase activity was not inhibited by vanadate, oligomycin, or nitrate, but was inhibited by relatively low concentrations of quercetin and the calmodulin inhibitor, compound 48/80. The NTPase was stimulated more than 50% by red light, and this effect was reversed by subsequent irradiation with far-red light. The photoreversibility of the stimulation indicated that the photoreceptor for this response was phytochrome, an important regulator of photomorphogenesis and gene expression in plants.
In Vivo Blue-Light Activation of Chlamydomonas reinhardii Nitrate Reductase 1
Azuara, Mar�a Pilar; Aparicio, Pedro J.
Chlamydomonas reinhardii cells, growing photoautotrophically under air, excreted to the culture medium much higher amounts of NO2? and NH4+ under blue than under red light. Under similar conditions, but with NO2? as the only nitrogen source, the cells consumed NO2? and excreted NH4+ at similar rates under blue and red light. In the presence of NO3? and air with 2% CO2 (v/v), no excretion of NO2? and NH4+ occurred and, moreover, if the bubbling air of the cells that were currently excreting NO2? and NH4+ was enriched with 2% CO2 (v/v), the previously excreted reduced nitrogen ions were rapidly reassimilated. The levels of total nitrate reductase and active nitrate reductase increased several times in the blue-light-irradiated cells growing on NO3? under air. When tungstate replaced molybdate in the medium (conditions that do not allow the formation of functional nitrate reductase), blue light activated most of the preformed inactive enzyme of the cells. Furthermore, nitrate reductase extracted from the cells in its inactive form was readily activated in vitro by blue light. It appears that under high irradiance (90 w m?2) and low CO2 tensions, cells growing on NO3? or NO2? may not have sufficient carbon skeletons to incorporate all the photogenerated NH4+. Because these cells should have high levels of reducing power, they might use NO3? or, in its absence, NO2? as terminal electron acceptors. The excretion of the products of NO2? and NH4+ to the medium may provide a mechanism to control reductant level in the cells. Blue light is suggested as an important regulatory factor of this photorespiratory consumption of NO3? and possibly of the whole nitrogen metabolism in green algae. PMID:16662818
Near-infrared imaging of fast intrinsic optical responses in visible light-activated amphibian retina.
Yao, Xin-Cheng; George, John S
High performance functional imaging is needed for dynamic measurements of neural processing in retina. Emerging techniques for visual prosthesis also require advanced methodology for reliable validation of electromagnetic stimulation of the retina. Imaging of fast intrinsic optical responses associated with neural activation promises a variety of technical advantages over traditional single and multichannel electrophysiological techniques for these purposes, but the application of fast optical signals for neural imaging has been limited by low signal-to-noise ratio and high background light intensity. However, by using an optimized near-infrared probe light and improved optical system, we improve the optical signals substantially, allowing single pass measurements with approximately micron resolution. We image fast intrinsic optical responses with different optical modalities, i.e., bright field, dark field, and cross-polarization, from isolated retina activated by visible light stimulation. At single cell resolution, bright-field imaging discloses the maxima of optical responses approximately 5% dI/I, where dI is the dynamic optical change and I is the baseline light intensity. Dark-field imaging techniques further enhance the sensitivity of optical measurements, and show the maxima of optical responses exceeding 10% dI/I. Cross-polarized imaging provides optical sensitivity similar to dark-field imaging, but different patterns of neural activation are observed. PMID:17212553
Floating Zone Growth and Scintillation Characteristics of Cerium-Doped Gadolinium Pyrosilicate Single Crystals
S. Kawamura; J. H. Kaneko; M. Higuchi; T. Yamaguchi; J. Haruna; Y. Yagi; K. Susa; F. Fujita; A. Homma; S. Nishiyama; K. Kurashige; H. Ishibashi; M. Furusaka
Growth of cerium-doped gadolinium pyrosilicate single crystals, which show 2.5 times greater light output for gamma-rays and five times greater light output for alpha-particles than GSO single crystals, is accomplished using the floating zone growth method (FZ method). Although growth of (GPS) single crystal is considered to be difficult because it melts incongruently according to the phase diagram of system,
High-efficiency white organic light-emitting diodes using thermally activated delayed fluorescence
NASA Astrophysics Data System (ADS)
Nishide, Jun-ichi; Nakanotani, Hajime; Hiraga, Yasuhide; Adachi, Chihaya
White organic light-emitting diodes (WOLEDs) have attracted much attention recently, aimed for next-generation lighting sources because of their high potential to realize high electroluminescence efficiency, flexibility, and low-cost manufacture. Here, we demonstrate high-efficiency WOLED using red, green, and blue thermally activated delayed fluorescence materials as emissive dopants to generate white electroluminescence. The WOLED has a maximum external quantum efficiency of over 17% with Commission Internationale de l'Eclairage coordinates of (0.30, 0.38).
High-efficiency white organic light-emitting diodes using thermally activated delayed fluorescence
Nishide, Jun-ichi; Hiraga, Yasuhide [Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); Hirata Corporation, 4-5 Iwano, Ueki, Kita, Kumamoto 861-0136 (Japan); Nakanotani, Hajime [Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); Innovative Organic Device Laboratory, Institute of Systems, Information Technologies and Nanotechnologies (ISIT), 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); Adachi, Chihaya, E-mail: firstname.lastname@example.com [Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); Innovative Organic Device Laboratory, Institute of Systems, Information Technologies and Nanotechnologies (ISIT), 744 Motooka, Nishi, Fukuoka 819-0395 (Japan); International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan)
White organic light-emitting diodes (WOLEDs) have attracted much attention recently, aimed for next-generation lighting sources because of their high potential to realize high electroluminescence efficiency, flexibility, and low-cost manufacture. Here, we demonstrate high-efficiency WOLED using red, green, and blue thermally activated delayed fluorescence materials as emissive dopants to generate white electroluminescence. The WOLED has a maximum external quantum efficiency of over 17% with Commission Internationale de l'Eclairage coordinates of (0.30, 0.38).
Inverted topside-emitting organic light-emitting diodes for active-matrix OLED displays
Thomas Dobbertin; Michael Kroger; Daniel Schneider; Eike Becker; Hans-Hermann Johannes; Wolfgang Kowalsky
Top-emitting organic light-emitting diodes (OLEDS) fornext-generation active-matrix OLED-displays (AM-OLEDs) arediscussed. The emission of light via the conductive transparent top-contact is considered necessary in terms of integrating OLED-technology to standard Si-based driver circuitry. The inverted OLED configuration (IOLED) in particular allows for the incorporation of more powerful n-channel field-effect transistors preferentially used for driver backplanes in AM-OLED displays. The use of
Lightening up Light Therapy: Activation of Retrograde Signaling Pathway by Photobiomodulation
Kim, Hong Pyo
Photobiomodulation utilizes monochromatic (or quasimonochromatic) light in the electromagnetic region of 600?1000 nm for the treatment of soft tissues in a nondestructive and nonthermal mode. It is conceivable that photobiomodulation is based upon the ability of the light to alter cell metabolism as it is absorbed by general hemoproteins and cytochrome c oxidase (COX) in particular. Recently it has been suggested radiation of visible and infrared (IR) activates retrograde signaling pathway from mitochondria to nucleus. In this review, the role of COX in the photobiomodulation will be discussed. Further a possible role of water as a photoreceptor will be suggested. PMID:25489415
Water-plasma-assisted synthesis of black titania spheres with efficient visible-light photocatalytic activity.
Panomsuwan, Gasidit; Watthanaphanit, Anyarat; Ishizaki, Takahiro; Saito, Nagahiro
Black titania spheres (H-TiO2-x) were synthesized via a simple green method assisted by water plasma at a low temperature and atmospheric pressure. The in situ production of highly energetic hydroxyl and hydrogen species from water plasma are the prominent factors in the oxidation and hydrogenation reactions during the formation of H-TiO2-x, respectively. The visible-light photocatalytic activity toward the dye degradation of H-TiO2-x can be attributed to the synergistic effect of large-surface area, visible-light absorption and the existence of oxygen vacancies and Ti(3+) sites. PMID:25946395
One to eight month X-ray light curves for active extragalactic objects
NASA Astrophysics Data System (ADS)
Snyder, W.
Light curves of 4 extragalactic objects obtained using the 0.5 to 20 keV LASS detectors on HEAO 1 are presented. Two of the objects are quasi-stellar sources; one is a BL Lacertae object; the fourth, although not unambiguously identified, is certainly extragalactic. In each case the light curves have a temporal resolution of a few days, and (because the sources are located at high ecliptic latitudes) extend at least 30 days in length. Variability is definitely detected in 3 of the 4 objects, suggesting that significant changes in flux may be common in active galaxies on monthly time scales.
Optical chirality without optical activity: How surface plasmons give a twist to light
Drezet, A; Laluet, J -Y; Ebbesen, T W
Light interacts differently with left and right handed three dimensional chiral objects, like helices, and this leads to the phenomenon known as optical activity. Here, by applying a polarization tomography, we show experimentally, for the first time in the visible domain, that chirality has a different optical manifestation for twisted planar nanostructured metallic objects acting as isolated chiral metaobjects. Our analysis demonstrate how surface plasmons, which are lossy bidimensional electromagnetic waves propagating on top of the structure, can delocalize light information in the just precise way for giving rise to this subtle effect.
Berges, John A.
DISTINCT PATTERNS OF NITRATE REDUCTASE ACTIVITY IN BROWN ALGAE: LIGHT AND AMMONIUM SENSITIVITY and lowest in summer. This is the first report of NR activity in any alga that is not strongly regulated the regulation of NR by light that has been observed in other algae and higher plants. Key index words: ammonium
Light-Intensity Activity Attenuates Functional Decline in Older Cancer Survivors
Blair, Cindy K.; Morey, Miriam C.; Desmond, Renee A.; Cohen, Harvey Jay; Sloane, Richard; Snyder, Denise C.; Demark-Wahnefried, Wendy
While moderate-vigorous intensity physical activities (MVPA) confer the greatest health benefits, evidence suggests that light-intensity activities are also beneficial, particularly for older adults and individuals with moderate-severe comorbidities. Purpose To examine cross-sectional and longitudinal associations between light-intensity activity and physical function in older cancer survivors at increased risk for age- and treatment-related comorbidities, including accelerated functional decline. Methods The analysis included data from 641 breast, prostate, and colorectal cancer survivors (54% female) aged 65 and older who participated in a 1-year, home-based diet and exercise intervention designed to reduce the rate of physical function decline. ANCOVA was used to compare means of physical function across levels of PA intensity (low-light (LLPA): 1.5-2.0 METs; high-light (HLPA): 2.1-2.9 METs; MVPA: ?3.0 METs). Results In cross-sectional analyses, increasing tertiles of light-intensity activity were associated with higher scores for all 3 measures of physical function (all p-values <0.005), after adjustment for age, sex, BMI, comorbidity, symptoms, and MVPA. Associations were stronger for HLPA than for LLPA. Compared with survivors who decreased or remained stable in MVPA and HLPA at the post-intervention follow-up, those who increased in HLPA, but decreased or remained stable in MVPA, reported higher physical function scores (LSMeans (95% CI): SF-36 physical function subscale: -5.58 (-7.96, -3.20) vs. -2.54 (-5.83, 0.75), p=0.14; basic lower extremity function: -2.00 (-3.45, -0.55) vs. 0.28 (-1.72, 2.28), p=0.07; advanced lower extremity function: -2.58 (-4.00, -1.15) vs. 0.44 (-1.52, 2.40), p=0.01). Conclusion Our findings suggest that increasing light-intensity activities, especially HLPA, may be a viable approach to reducing the rate of physical function decline in individuals who are unable or reluctant to initiate or maintain adequate levels of moderate-intensity activities. PMID:24389524
[Study on the experimental application of floating-reference method to noninvasive blood glucose sensing].
Yu, Hui; Qi, Dan; Li, Heng-da; Xu, Ke-xin; Yuan, Wei-jie
Weak signal, low instrument signal-to-noise ratio, continuous variation of human physiological environment and the interferences from other components in blood make it difficult to extract the blood glucose information from near infrared spectrum in noninvasive blood glucose measurement. The floating-reference method, which analyses the effect of glucose concentration variation on absorption coefficient and scattering coefficient, gets spectrum at the reference point and the measurement point where the light intensity variations from absorption and scattering are counteractive and biggest respectively. By using the spectrum from reference point as reference, floating-reference method can reduce the interferences from variation of physiological environment and experiment circumstance. In the present paper, the effectiveness of floating-reference method working on improving prediction precision and stability was assessed through application experiments. The comparison was made between models whose data were processed with and without floating-reference method. The results showed that the root mean square error of prediction (RMSEP) decreased by 34.7% maximally. The floating-reference method could reduce the influences of changes of samples' state, instrument noises and drift, and improve the models' prediction precision and stability effectively. PMID:22582650
Individual and combined suppressive effects of submerged and floating-leaved macrophytes on algal blooms.
Seto, Mayumi; Takamura, Noriko; Iwasa, Yoh
Shallow lakes and ponds are often characterised either by clear water with abundant submerged macrophytes or by turbid water with abundant phytoplankton. Blooms of toxic filamentous blue-green algae (cyanobacteria) often dominate the phytoplankton community in eutrophic lakes, which threatens ecological functions and biodiversity of freshwater ecosystems. We studied a simple lake model in order to evaluate individual and combined suppressive effects of rooted submerged and rooted floating-leaved macrophytes on algal blooms. Floating-leaved plants are superior competitors for light, whereas submerged plants absorb and reduce available phosphorus in a water column that rooted floating-leaved plants exploit to a lesser extent. We found that mixed vegetation that includes both submerged and floating-leaved plants is more resistant than vegetation comprised by a single plant type to algal invasion triggered by phosphorus loading. In addition, competitive exclusion of submerged plants by floating-leaved plants may promote an algal bloom. These predictions were confirmed by the decision tree analysis of field data from 35 irrigation ponds in Hyogo Prefecture, Japan. PMID:23219493
A spinal opsin controls early neural activity and drives a behavioral light response.
Friedmann, Drew; Hoagland, Adam; Berlin, Shai; Isacoff, Ehud Y
Nonvisual detection of light by the vertebrate hypothalamus, pineal, and retina is known to govern seasonal and circadian behaviors. However, the expression of opsins in multiple other brain structures suggests a more expansive repertoire for light regulation of physiology, behavior, and development. Translucent zebrafish embryos express extraretinal opsins early on, at a time when spontaneous activity in the developing CNS plays a role in neuronal maturation and circuit formation. Though the presence of extraretinal opsins is well documented, the function of direct photoreception by the CNS remains largely unknown. Here, we show that early activity in the zebrafish spinal central pattern generator (CPG) and the earliest locomotory behavior are dramatically inhibited by physiological levels of environmental light. We find that the photosensitivity of this circuit is conferred by vertebrate ancient long opsin A (VALopA), which we show to be a G?(i)-coupled receptor that is expressed in the neurons of the spinal network. Sustained photoactivation of VALopA not only suppresses spontaneous activity but also alters the maturation of time-locked correlated network patterns. These results uncover a novel role for nonvisual opsins and a mechanism for environmental regulation of spontaneous motor behavior and neural activity in a circuit previously thought to be governed only by intrinsic developmental programs. PMID:25484291
AgVO3 nanorods: Synthesis, characterization and visible light photocatalytic activity
NASA Astrophysics Data System (ADS)
Sivakumar, V.; Suresh, R.; Giribabu, K.; Narayanan, V.
Large scale and high purity silver vanadate (AgVO3) nanorods were synthesized by thermal decomposition method. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, Ultraviolet-Visible (DRS-UV-Visible) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to characterize the structure, light absorption capacity and morphology of the as-synthesized sample. The photocatalytic activity of AgVO3 nanorods was examined by degradation of methylene blue (MB) as a model organic pollutant. The degradation efficiency is 85.02% in the 120 min visible light illumination. Further, the AgVO3 nanorods were used as a photocatalyst for industrial effluent. 95.4% degradation efficiency was obtained within the visible light irradiation of 120 min. The possible photocatalytic mechanism has also been proposed.
Effects of temperature and photosynthetic inhibitors on light activation of C4-phosphoenolpyruvate carboxylase.
Samaras, Y; Manetas, Y; Gavalas, N A
Phosphoenolpyruvate carboxylase from leaves of the C4 plant Setaria verticillata (L.) Beauv. is activated by light; day levels of activity are reached after 30 minutes of illumination. Photoactivation is prevented by inhibitors of photosynthetic electron flow or of photophosphorylation and by D,L-glyceraldehyde, which inhibits the reductive pentose phosphate pathway.Although the extractable activity in the dark is not affected by temperature the photoactivation is prevented when both illumination and extraction are done under low temperature (5 C). High temperature (30 C) during either illumination or extraction is needed for activation. Once the enzyme is photoactivated at 30 C, a transfer of the leaves to 5 C does not abolish the extra activity.The results suggest that both unimpaired electron flow and photophosphorylation are prerequisites for the activation of phosphoenolpyruvate carboxylase. Low temperature apparently suppresses either the transport to the cytoplasm of a photosynthetic intermediate or the activating reaction itself. The inclusion of phosphoenolpyruvate in the extraction medium increases the night activity.On the basis of the available information, it is suggested that phosphoenolpyruvate could be the activator in vivo. In that case, the activation of phosphoenolpyruvate carboxylase would depend on internal CO2 level and prior photoactivation of both pyruvate, orthophosphate, dikinase and NADP malate dehydrogenase. PMID:24429530
Light Intensity and Carbon Dioxide Availability Impact Antioxidant Activity in Green Onions (Allium fistulosumm L)
NASA Astrophysics Data System (ADS)
Levine, Lanfang; Bisbee, Patricia; Pare, Paul
The prospect of long-duration manned space missions poses many challenges, including the development of a sustainable life support system and effective methods of space-radiation protection. To mitigate the risk of increased space-radiation, functional foods rich in antioxidant properties such as green onions are of particular interest. However it has yet to be established whether antioxidant properties can be preserved or enhanced in space environment where carbon dioxide, lighting intensity, gravity and pressure differ from which plants have acclimated to on earth. In this study, green onions (Allium fistulosumm L. cultivar Kinka) rich in antioxidant flavonoids are used as a model system to investigate variations in antioxidant capacity with plants grown under varying light intensities and CO2 concentrations. The antioxidant potential is determined using both radical cation scavenging and oxygen radical absorbance assays. For all light intensities assayed, antioxidant potential in water extract of green onions per gram biomass declined with CO2 increases up to 1200 ppm, and then leveled off with further CO2 increase to 4000 ppm. This inverse carbon dioxide versus antioxidant activity correlation suggests lower accumulation rates for water soluble antioxidant compounds compared to total biomass under increasing CO2 concentrations. The effect of increasing atmospheric CO2 concentration on antioxidant activity of ethanol extracts were light intensity dependent. The implications of these findings are discussed in the context of traditional plant antioxidants including vitamin C and the major onion flavonoid quercetin.
Photo-induced bending in a light-activated polymer laminated composite.
Mu, Xiaoming; Sowan, Nancy; Tumbic, Julia A; Bowman, Christopher N; Mather, Patrick T; Qi, H Jerry
Light activated polymers (LAPs) have attracted increasing attention since these materials change their shape and/or behavior in response to light exposure, which serves as an instant, remote and precisely controllable stimulus that enables non-contact control of the material shape and behavior through simple variation in light intensity, wavelength and spatially controlled exposure. These features distinguish LAPs from other active polymers triggered by other stimuli such as heat, electrical field or humidity. Previous examples have resulted in demonstrations in applications such as surface patterning, photo-induced shape memory behavior, and photo-origami. However, in many of these applications, an undesirable limitation has been the requirement to apply and maintain an external load during light irradiation. In this paper, a laminated structure is introduced to provide a pre-programmed stress field, which is then used for photo-induced deformation. This laminated structure is fabricated by bonding a stretched elastomer (NOA65) sheet between two LAP layers. Releasing the elastomer causes contraction and introduces a compressive stress in the LAPs, which are relaxed optically to trigger the desired deformation. A theoretical model is developed to quantitatively examine the laminated composite system, allowing exploration of the design space and optimum design of the laminate. PMID:25690905
Optimization of an advanced non-invasive light activated disinfection strategy
NASA Astrophysics Data System (ADS)
George, S.; Kishen, A.
A photosensitizer formulation and strategy was developed based on the photophysical, photochemical and photobiological characteristics of methylene blue (MB) for the disinfection of root canal using light activated therapy. Disinfection of matured E. faecalis biofilms on root canal dentine was tried with the newly developed 'Advanced Non- Invasive Light Activated Disinfection' (ANILAD), conventional photodynamic therapy, and conventional root canal therapy alone or in combination with ANILAD. The results showed that, although complete disinfection of nonmatured biofilm is possible by ANILAD alone, a combination of conventional root canal treatment (RCT) with ANILAD could achieve significantly higher bacterial killing (6log 10-7log 10 bacterial reduction) compared to any other tested treatment in matured biofilm (p<0.001).
Preparation and characterization of porous C-modified anatase titania films with visible light catalytic activity
Xie Yi [Key Laboratory of Silicate Materials Science and Engineering, Wuhan University of Technology, Ministry of Education, Wuhan, Hubei 430070 (China); Zhao Xiujian [Key Laboratory of Silicate Materials Science and Engineering, Wuhan University of Technology, Ministry of Education, Wuhan, Hubei 430070 (China)], E-mail: email@example.com; Chen Yunxia; Zhao Qingnan; Yuan Qihua [Key Laboratory of Silicate Materials Science and Engineering, Wuhan University of Technology, Ministry of Education, Wuhan, Hubei 430070 (China)
Visible-light-activated C-modified anatase titania films have been synthesized from TiCl{sub 4} and carbonic ink by using the sol-gel route. The synthesized photocatalysts were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and optical measurements. The modifying carbon not only produces homogeneous worm-like structure with uniform pores, but also extends the absorbance spectra of the as-prepared films into visible region. The results of visible-light-induced degradation of methyl orange (MO) show that the C-modified titania films exhibits much higher photocatalytic activities than that of pure titania film prepared at the same conditions. - Graphical abstract: Carbon modifying not only produces homogeneous worm-like structure with uniform pores, but also extends the absorbance spectra of the as-prepared titania films into visible region.
Development of White-Light Emitting Active Layers in Nitride Based Heterostructures for Phosphorless Solid State Lighting
Jan Talbot; Kailash Mishra
This report provides a summary of research activities carried out at the University of California, San Diego and Central Research of OSRAM SYLVANIA in Beverly, MA partially supported by a research contract from US Department of Energy, DE-FC26-04NT422274. The main objective of this project was to develop III-V nitrides activated by rare earth ions, RE{sup 3+}, which could eliminate the need for phosphors in nitride-based solid state light sources. The main idea was to convert electron-hole pairs injected into the active layer in a LED die to white light directly through transitions within the energy levels of the 4f{sup n}-manifold of RE{sup 3+}. We focused on the following materials: Eu{sup 3+}(red), Tb{sup 3+}(green), Er{sup 3+}(green), Dy{sup 3+}(yellow) and Tm{sup 3+}(blue) in AlN, GaN and alloys of AlN and GaN. Our strategy was to explore candidate materials in powder form first, and then study their behavior in thin films. Thin films of these materials were to be deposited on sapphire substrates using pulsed laser deposition (PLD) and metal organic vapor phase epitaxy (MOVPE). The photo- and cathode-luminescence measurements of these materials were used to investigate their suitability for white light generation. The project proceeded along this route with minor modifications needed to produce better materials and to expedite our progress towards the final goal. The project made the following accomplishments: (1) red emission from Eu{sup 3+}, green from Tb{sup 3+}, yellow from Dy{sup 3+} and blue from Tm{sup 3+} in AlN powders; (2) red emission from Eu{sup 3+} and green emission from Tb{sup 3+} in GaN powder; (3) red emission from Eu{sup 3+} in alloys of GaN and AlN; (4) green emission from Tb{sup 3+} in GaN thin films by PLD; (5) red emission from Eu{sup 3+} and Tb{sup 3+} in GaN thin films deposited by MOVPE; (6) energy transfer from host to RE{sup 3+}; (7) energy transfer from Tb{sup 3+} to Eu{sup 3+} in AlN powders; (8) emission from AlN powder samples codoped with (Eu{sup 3+} ,Tb{sup 3+} ) and (Dy{sup 3+}, Tm{sup 3+}); and (9) white emission from AlN codoped with Dy{sup 3+} and Tm{sup 3+}. We also extensively studied the stabilities of rare earth ions in GaN, and the nature of oxygen defects in GaN and its impact on the optical properties of the host material, using first principles method. Results from these theoretical calculations together with fluorescence measurements from the materials essentially proved the underlying concepts for generating white light using RE{sup 3+}-activated nitrides. For this project, we successfully built a horizontal MOVPE reactor and used it to deposit thin films of undoped and doped nitrides of GaN and InGaN, which is a very significant achievement. Since this reactor was designed and built by in-house experts, it could be easily modified and reassembled for specific research purposes. During this study, it was successfully modified for homogeneous distribution of rare earth ions in a deposited film. It will be an ideal tool for future research involving novel thin film material concepts. We examined carefully the suitability of various metal organic precursors for incorporating RE{sup 3+}. In order to avoid oxygen contamination, several oxygen-free RE{sup 3+} precursors were identified. Both oxygen-free and oxygen- containing metal organic precursors were used for certain rare earth ions (Eu{sup 3+}, Tb{sup 3+} and Er{sup 3+}). However, the suitability of any particular type of precursor for MOVPE deposition was not established during this study, and further study is needed. More intensive research in the future is needed to improve the film quality, and eliminate the separation of rare earth oxide phases during the deposition of thin films by MOVPE. The literature in the area of the chemistry of rare earth ions in nitrides is almost nonexistent, in spite of the significant research on luminescence of RE{sup 3+} in nitrides. Consequently, MOVPE as a method of deposition of RE{sup 3+}-activated nitrides is relatively unexplored. In the following sections of this report, the ou
Electroluminescence properties of rare-earth-activated SrS thin films under light irradiation
Isao Tanaka; Yoshitaka Izumi; Katsu Tanaka; Yoji Inoue; Shinji Okamoto
We have investigated the effects of external light irradiation on the electroluminescence properties of SrS thin films activated with Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, and Tm in order to clarify the generation mechanism of the dynamic space charge. The photo-induced space charge is observed in all of our fabricated devices, and that of SrS:Ce is the
Regulating gene expression in human leukemia cells using light-activated oligodeoxynucleotides
XinJing Tang; Jyothishmathi Swaminathan; Alan M. Gewirtz; Ivan J. Dmochowski
Light-activated antisense oligodeoxynucleotides (asODNs) were developed to control the degradation of target mRNA in living cells by RNase H. A 20-mer asODN previously shown to target c-myb, a hema- topoietic transcription factor, was covalently attached via a photocleavable linker (PL) to partially complementary 20-mer sense strands (sODNs). In the 'caged' state, the sODN blocked hybridization of the asODN to c-myb
Octahedral-shaped perovskite nanocrystals and their visible-light photocatalytic activity.
Yin, Simin; Tian, He; Ren, Zhaohui; Wei, Xiao; Chao, Chunying; Pei, Jingyuan; Li, Xiang; Xu, Gang; Shen, Ge; Han, Gaorong
Octahedral-shaped perovskite PbTiO3 nanocrystals (PT OCT) with well-defined {111} facets exposed have been successfully synthesized via a facile hydrothermal method by using LiNO3 as an ion surfactant. The Li-O bond on the surface of PT OCT nanocrystals is essential to the stability of such nanocrystals and also results in a dramatic high visible-light photocatalytic activity. PMID:24769605
Facile synthesis of phosphorus doped graphitic carbon nitride polymers with enhanced visible-light photocatalytic activity
Zhang, Ligang [Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Chen, Xiufang; Guan, Jing; Jiang, Yijun; Hou, Tonggang [Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Mu, Xindong, E-mail: firstname.lastname@example.com [Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China)
Graphical abstract: - Highlights: � P-doped g-C{sub 3}N{sub 4} has been prepared by a one-pot green synthetic approach. � The incorporation of P resulted in favorable textural and electronic properties. � Doping with P enhanced the visible-light photocatalytic activity of g-C{sub 3}N{sub 4}. � A postannealing treatment further enhanced the activity of P-doped g-C{sub 3}N{sub 4}. � Photogenerated holes were the main species responsible for the activity. - Abstract: Phosphorus-doped carbon nitride materials were prepared by a one-pot green synthetic approach using dicyandiamide monomer and a phosphorus containing ionic liquid as precursors. The as-prepared materials were subjected to several characterizations and investigated as metal-free photocatalysts for the degradation of organic pollutants (dyes like Rhodamine B, Methyl orange) in aqueous solution under visible light. Results revealed that phosphorus-doped carbon nitride have a higher photocatalytic activity for decomposing Rhodamine B and Methyl orange in aqueous solution than undoped g-C{sub 3}N{sub 4}, which was attributed to the favorable textural, optical and electronic properties caused by doping with phosphorus heteroatoms into carbon nitride host. A facile postannealing treatment further improved the activity of the photocatalytic system, due to the higher surface area and smaller structural size in the postcalcined catalysts. The phosphorus-doped carbon nitride showed high visible-light photocatalytic activity, making them promising materials for a wide range of potential applications in photochemistry.
UV and visible light active aqueous titanium dioxide colloids stabilized by surfactants.
Pacia, Micha?; Warszy?ski, Piotr; Macyk, Wojciech
Attempts to increase the stability of photocatalytically active nanodispersions of titanium dioxide over a wide range of pH (3-10) were undertaken. Polyethylene glycols (PEGs) with different molecular weights and polyoxyethylenesorbitan monooleate (Tween� 80) were tested as stabilizing agents of TiO2 nanoparticles. The results of DLS measurements proved the stabilizing effect of Tween� 80 while the systems involving PEGs, independently of the polymer concentration, showed a tendency to form aggregates in neutral solutions. The colloids stabilized with Tween� 80 were photosensitized with 2,3-naphthalenediol (nd) or 2-hydroxy-3-naphthoic acid (hn) or catechol (cat). The photocatalytic activity of such colloids has been assessed in an azure B degradation reaction using both UV and visible light. The nd@TiO2 + Tween colloid appeared particularly photoactive upon visible light irradiation. Moreover, the comparison of activities of nd@TiO2 + Tween and TiO2 + Tween revealed a significantly better performance of the former nanodispersion, independently of the irradiation conditions (UV or visible light). This effect has been explained by different structures of micelles formed in the case of TiO2 and nd@TiO2 stabilized with Tween� 80. PMID:24781390
The Stellar Activity of an M Dwarf Binary from Deconvolved Kepler Light Curves
NASA Astrophysics Data System (ADS)
Lurie, John C.; Davenport, James R. A.; Hawley, Suzanne L.; Wilkinson, Tessa D.
The M5+M5 pair GJ 1245AB was monitored almost continuously by Kepler for four years, providing a unique opportunity to study the stellar activity of two coeval, nearly-equal mass M dwarfs that are fully convective. The stars are 7" apart on the sky, and separate light curves for each star cannot be generated via aperture photometry due to Kepler's large 4"/pixel plate scale. Instead, we generated separate light curves from the target pixel files using the PyKE pixel response function modeling procedures. Intriguingly, the angular separation of the two stars decreases over the four years of Kepler observations in a manner consistent with an astrometric perturbation from the much fainter, unseen M8 (GJ 1245C) companion to GJ 1245A. Analyzing the separated light curves, we observe long lived starspot features on both stars that evolve on multi-year timescales. Both stars flare at nearly the same rate, despite having rotation rates that differ by almost a factor of three. Consistent with recent studies of active M dwarf binaries, these results provide further insight into the roles of age and rotation rate in stellar activity.
Active display and encoding by integrated plasmonic polarizer on light-emitting-diode.
Wang, L; Li, T; Guo, R Y; Xia, W; Xu, X G; Zhu, S N
An electrical pumped microscopic active display with integration of plasmonic polarizer and light-emitting-diode is proposed. Thanks to the strong polarized emission through the rectangular nanoholes, well designed pixels with respect to different polarizations are engineered, which give rise to flexible and controllable active display. As results, polarization multiplexed letter encoding, single and double gray-scale images and animation movies are successfully realized. Our results demonstrate a new strategy in electro-optical integration and indicate potential applications in designing new type of microscopic electro-optical devices. PMID:24008314
Simultaneous whole-animal 3D-imaging of neuronal activity using light field microscopy
Prevedel, R; Hoffmann, M; Pak, N; Wetzstein, G; Kato, S; Schr�del, T; Raskar, R; Zimmer, M; Boyden, E S; Vaziri, A
3D functional imaging of neuronal activity in entire organisms at single cell level and physiologically relevant time scales faces major obstacles due to trade-offs between the size of the imaged volumes, and spatial and temporal resolution. Here, using light-field microscopy in combination with 3D deconvolution, we demonstrate intrinsically simultaneous volumetric functional imaging of neuronal population activity at single neuron resolution for an entire organism, the nematode Caenorhabditis elegans. The simplicity of our technique and possibility of the integration into epi-fluoresence microscopes makes it an attractive tool for high-speed volumetric calcium imaging.
Effect of Dopant Activation on Device Characteristics of InGaN-based Light Emitting Diodes
NASA Astrophysics Data System (ADS)
Lacroce, Nicholas; Liu, Guangyu; Tan, Chee-Keong; Arif, Ronald A.; Lee, Soo Min; Tansu, Nelson
Achieving high uniformity in growths and device characteristics of InGaN-based light-emitting diodes (LEDs) is important for large scale manufacturing. Dopant activation and maintaining control of variables affecting dopant activation are critical steps in the InGaN-based light emitting diodes (LEDs) fabrication process. In the epitaxy of large scale production LEDs, in-situ post-growth annealing is used for activating the Mg acceptor dopant in the p-AlGaN and p-GaN of the LEDs. However, the annealing temperature varies with respect to position in the reactor chamber, leading to severe uniform dopant activation issue across the devices. Thus, it is important to understand how the temperature gradient and the resulting variance in Mg acceptor activation will alter the device properties. In this work, we examine the effect of varying p-type doping levels in the p-GaN layers and AlGaN electron blocking layer of the GaN LEDs on the optoelectronic properties including the band profile, carrier concentration, current density, output power and quantum efficiency. By understanding the variations and its effect, the identification of the most critical p-type doping layer strategies to address this variation will be clarified.
Microwave hydrothermal synthesis of AgInS{sub 2} with visible light photocatalytic activity
Zhang, Wenjuan [Research Institute of Photocatalysis, State Key Laboratory Breeding Base of Photocatalysis, Fuzhou University, Gongye Road No. 523, Fuzhou 350002, Fujian (China)] [Research Institute of Photocatalysis, State Key Laboratory Breeding Base of Photocatalysis, Fuzhou University, Gongye Road No. 523, Fuzhou 350002, Fujian (China); Li, Danzhen, E-mail: firstname.lastname@example.com [Research Institute of Photocatalysis, State Key Laboratory Breeding Base of Photocatalysis, Fuzhou University, Gongye Road No. 523, Fuzhou 350002, Fujian (China)] [Research Institute of Photocatalysis, State Key Laboratory Breeding Base of Photocatalysis, Fuzhou University, Gongye Road No. 523, Fuzhou 350002, Fujian (China); Chen, Zhixin; Sun, Meng; Li, Wenjuan; Lin, Qiang; Fu, Xianzhi [Research Institute of Photocatalysis, State Key Laboratory Breeding Base of Photocatalysis, Fuzhou University, Gongye Road No. 523, Fuzhou 350002, Fujian (China)] [Research Institute of Photocatalysis, State Key Laboratory Breeding Base of Photocatalysis, Fuzhou University, Gongye Road No. 523, Fuzhou 350002, Fujian (China)
Highlights: {yields} AgInS{sub 2} nanoparticles were synthesized by a microwave hydrothermal method. {yields} This method involves no organic solvents, catalysts, or surfactants. {yields} AgInS{sub 2} showed higher activity for photocatalytic degradation MO than TiO{sub 2-x}N{sub x}. {yields} Holes, O{sub 2}{center_dot}{sup -}, and H{sub 2}O{sub 2} played an important role in the photocatalytic process. -- Abstract: AgInS{sub 2} nanoparticles with superior visible light photocatalytic activity were successfully synthesized by a microwave hydrothermal method. This method is a highly efficient and rapid route that involves no organic solvents, catalysts, or surfactants. The photocatalytic activity of AgInS{sub 2} nanoparticles was investigated through the degradation of dyes under visible light irradiation. Compared with TiO{sub 2-x}N{sub x}, AgInS{sub 2} has exhibited a superior activity for photocatalytic degradation MO under the same condition. The experiment results showed that superoxide radicals (O{sub 2}{center_dot}{sup -}), hydrogen peroxides (H{sub 2}O{sub 2}) and holes (h{sup +}) were the mainly active species for the degradation of organic pollutants over AgInS{sub 2}. Through the determination of flat band potential, the energy band structure of the sample was obtained. A possible mechanism for the degradation of organic pollutant over AgInS{sub 2} was proposed.
Activation of microcomponents with light for micro-electro-mechanical systems and micro-optical-electro-mechanical systems applications
Robert C. Gauthier; R. Niall Tait; Mike Ubriaco
We examine the light-activation properties of micrometer-sized gear structures fabricated with polysilicon surface micromachining techniques. The gears are held in place on a substrate through a capped anchor post and are free to rotate about the post. The light-activation technique is modeled on photon radiation pressure, and the equation of motion of the gear is solved for this activation technique.
Influence of Different Light Conditions on Root Fe3+ Reductase Activity of Iron-Deficient Cucumber Plants
XU Liang-zheng; LIU Zhi-wei; LIU Hui-na; LIAO Fu-lin
Objective)To ascertain the influence of different light conditions on root Fe3+ reductase activity of iron-deficient cucumber plants.(Method)The effects of different light conditions on Fe3+ reductase activity in Fe-deficiency cucumber (Cucumis stativus L.) were studied in solution culture. Fe3+ reductase activity in roots of cucumber plants, chlorophyll content in leaves of cucumber seedling, soluble total sugar and sucrose content in shoot
Floating seal system for rotary devices
Banasiuk, H.A.
This invention relates to a floating seal system for rotary devices to reduce gas leakage around the rotary device in a duct and across the face of the rotary device to an adjacent duct. The peripheral seal bodies are made of resilient material having a generally U-shaped cross section wherein one of the legs is secured to a support member and the other of the legs forms a contacting seal against the rotary device. The legs of the peripheral seal form an extended angle of intersection of about 10[degree] to about 30[degree] in the unloaded condition to provide even sealing forces around the periphery of the rotary device. The peripheral seal extends around the periphery of the support member except where intersected by radial seals which reduce gas leakage across the face of the rotary device and between adjacent duct portions. The radial seal assembly is fabricated from channel bars, the smaller channel bar being secured to the divider of the support member and a larger inverted rigid floating channel bar having its legs freely movable over the legs of the smaller channel bar forming therewith a tubular channel. A resilient flexible tube is positioned within the tubular channel for substantially its full length to reduce gas leakage across the tubular channel. A spacer extends beyond the face of the floating channel near each end of the floating channel a distance to provide desired clearance between the floating channel and the face of the rotary device. 5 figs.
Floating seal system for rotary devices
Banasiuk, Hubert A. (Chicago, IL)
This invention relates to a floating seal system for rotary devices to reduce gas leakage around the rotary device in a duct and across the face of the rotary device to an adjacent duct. The peripheral seal bodies are made of resilient material having a generally U-shaped cross section wherein one of the legs is secured to a support member and the other of the legs forms a contacting seal against the rotary device. The legs of the peripheral seal form an extended angle of intersection of about 10.degree. to about 30.degree. in the unloaded condition to provide even sealing forces around the periphery of the rotary device. The peripheral seal extends around the periphery of the support member except where intersected by radial seals which reduce gas leakage across the face of the rotary device and between adjacent duct portions. The radial seal assembly is fabricated from channel bars, the smaller channel bar being secured to the divider of the support member and a larger inverted rigid floating channel bar having its legs freely movable over the legs of the smaller channel bar forming therewith a tubular channel. A resilient flexible tube is positioned within the tubular channel for substantially its full length to reduce gas leakage across the tubular channel. A spacer extends beyond the face of the floating channel near each end of the floating channel a distance to provide desired clearance between the floating channel and the face of the rotary device.
Conjugated polymer nanoparticles for light-activated anticancer and antibacterial activity with imaging capability.
Chong, Hui; Nie, Chenyao; Zhu, Chunlei; Yang, Qiong; Liu, Libing; Lv, Fengting; Wang, Shu
A new water-soluble conjugated polymer containing fluorene and boron-dipyrromethene repeat units in the backbones (PBF) that exhibits red emission was synthesized and characterized. Cationic PBF forms uniform nanoparticles with negatively charged disodium salt 3,3'-dithiodipropionic acid (SDPA) in aqueous solution through electrostatic interactions. The nanoparticles display absorption maximum at 550 nm and emission maximum at 590 nm. Upon photoexcitation with white light (400-800 nm) with 90 and 45 mW�cm(-2) for bacteria and cancer cells killing respectively, PBF nanoparticles can sensitize the oxygen molecule to readily produce reactive oxygen species (ROS) for rapidly killing neighboring bacteria and cancer cells. Furthermore, PBF nanoparticles concurrently provide optical imaging capability. PBF nanoparticles are therefore a promising multifunctional material for treating cancers and bacteria infections, while concurrently providing optical monitoring capabilities. PMID:22054172
Visible light activated photocatalytic behaviour of rare earth modified commercial TiO{sub 2}
Tobaldi, D.M., E-mail: firstname.lastname@example.com [Department of Materials and Ceramic Engineering/CICECO, University of Aveiro, Campus Universit�rio de Santiago, 3810-193 Aveiro (Portugal); Pullar, R.C. [Department of Materials and Ceramic Engineering/CICECO, University of Aveiro, Campus Universit�rio de Santiago, 3810-193 Aveiro (Portugal); �kapin, A. Sever [Slovenian National Building and Civil Engineering Institute, Dimi?eva 12, SI-1000 Ljubljana (Slovenia); Seabra, M.P.; Labrincha, J.A. [Department of Materials and Ceramic Engineering/CICECO, University of Aveiro, Campus Universit�rio de Santiago, 3810-193 Aveiro (Portugal)
Highlights: � RE gave more surface hydroxyl groups attached to the photocatalyst's surface. � RE gave the modified and fired samples a high specific surface area. � Photocatalytic activity was assessed in gas�solid phase under visible-light exposure. � Thermal treated RE-TiO{sub 2}s showed a superior visible-light photocatalytic activity. � La-TiO{sub 2} was the best performing photocatalyst. - Abstract: A commercial TiO{sub 2} nanopowder, Degussa P25, was modified with several rare earth (RE) elements in order to extend its photocatalytic activity into the visible range. The mixtures were prepared via solid-state reaction of the precursor oxides, and thermally treated at high temperature (900 and 1000 �C), with the aim of investigating the photocatalytic activity of the thermally treated samples. This thermal treatment was chosen for a prospective application as a surface layer in materials that need to be processed at high temperatures. The photocatalytic activity (PCA) of the samples was assessed in gas�solid phase � monitoring the degradation of isopropanol (IPA) � under visible-light irradiation. Results showed that the addition of the REs lanthanum, europium and yttrium to TiO{sub 2} greatly improved its photocatalytic activity, despite the thermal treatment, because of the presence of more surface hydroxyl groups attached to the photocatalyst's surface, together with a higher specific surface area (SSA) of the modified and thermally treated samples, with regard to the unmodified and thermally treated Degussa P25. The samples doped with La, Eu and Y all had excellent PCA under visible-light irradiation, even higher than the untreated Degussa P25 reference sample, despite their thermal treatment at 900 �C, with lanthanum producing the best results (i.e. the La-, Eu- and Y-TiO{sub 2} samples, thermally treated at 900 �C, had, respectively, a PCA equal to 26, 27 and 18 ppm h{sup ?1} � in terms of acetone formation � versus 15 ppm h{sup ?1} for the 900 �C thermally treated Degussa P25). On the other hand, Ce�TiO{sub 2}s had no significant photocatalytic activity.
Titania produced from Ti-salt flocculated sludge: photocatalytic activity under solar light.
Shon, Ho Kyong; Okour, Yousef; Park, Se Min; Kim, Jong Beom; Kim, Jong-Ho
In this study, titania photocatalyst was produced from the wastewater sludge of Ti-salt flocculation. The high photocatalytic activity of titania reported was evaluated based on a single organic substrate. However, the photocatalytic activity is a substrate-specific; one photocatalyst showed different photocatalytic degradation rates for different substrates. Thus, to investigate the substrate-specific photocatalytic activity of titania, various substrates of humic acid (HA), dichloroacetic acid (DCA), rhodamine B (RhB), metsulfuron methyl (M&M) and phenol were used under simulated solar light irradiation. Results showed titania had a high activity rate for RhB, moderate activity for HA and DCA and low activity for M&M and phenol indicating substrate-specific activities. When compared with Degussa-P25, titania showed higher activity for M&M, while the opposite was observed for HA and phenol. The specific-substrate behaviour of titania could depend on specific physicochemical and electronic interactions between titania, substrates, and their intermediates compounds formed. PMID:25936122
Assessment of disease activity in Systemic Lupus Erythematosus: Lights and shadows.
Ceccarelli, Fulvia; Perricone, Carlo; Massaro, Laura; Cipriano, Enrica; Alessandri, Cristiano; Spinelli, Francesca Romana; Valesini, Guido; Conti, Fabrizio
The assessment of disease activity in patients affected by Systemic Lupus Erythematosus (SLE) represents an important issue, as recommended by the European League Against Rheumatism (EULAR). Two main types of disease activity measure have been proposed: the global score systems, providing an overall measure of activity, and the individual organ/system assessment scales, assessing disease activity in different organs. All the activity indices included both clinical and laboratory items, related to the disease manifestations. However, there is no gold standard to measure disease activity in patients affected by SLE. In this review, we will analyze the lights and shadows of the disease activity indices, by means of a critical approach. In particular, we will focus on SLE Disease Activity Index (SLEDAI) and British Isles Lupus Assessment Group (BILAG), the most frequently used in randomized controlled trials and observational studies. The evaluation of data from the literature underlined some limitations of these indices, making their application in clinical practice difficult and suggesting the possible use of specific tools in the different subset of SLE patients, in order to capture all the disease features. PMID:25742757
Band gap narrowing of titanium dioxide (TiO2) nanocrystals by electrochemically active biofilms and their visible light activity.
Kalathil, Shafeer; Khan, Mohammad Mansoob; Ansari, Sajid Ali; Lee, Jintae; Cho, Moo Hwan
We report a simple biogenic-route to narrow the band gap of TiO2 nanocrystals for visible light application by offering a greener method. When an electrochemically active biofilm (EAB) was challenged with a solution of Degussa-TiO2 using sodium acetate as the electron donor, greyish blue-colored TiO2 nanocrystals were obtained. A band gap study showed that the band gap of the modified TiO2 nanocrystals was significantly reduced (E(g) = 2.85 eV) compared to the unmodified white Degussa TiO2 (E(g) = 3.10 eV). PMID:23760526
Floating photocatalysts based on TiO 2 grafted on expanded polystyrene beads for the solar degradation of dyes
F. Magalh�es; R. M. Lago
In this work, a highly active, low cost, simple and robust floating photocatalyst based on TiO2 P25 grafted on expanded polystyrene (EPS) beads was developed. SEM and TG analyses showed that ca. 18wt% of TiO2 can be permanently grafted on the surface of EPS particles. This floating photocatalyst showed high efficiency for the degradation of three different dyes, i.e. methylene
Floating zone melting of cadmium telluride
NASA Technical Reports Server (NTRS)
Chang, Wen-Ming; Regel, L. L.; Wilcox, W. R.
To produce superior crystals of cadmium telluride, floating zone melting in space has been proposed. Techniques required for floating zone melting of cadmium telluride are being developed. We have successfully float-zoned cadmium telluride on earth using square rods. A resistance heater was constructed for forming the molten zone. Evaporation of the molten zone was controlled by adding excess cadmium to the growth ampoule combined with heating of the entire ampoule. An effective method to hold the feed rod was developed. Slow rotation of the growth ampoule was proven experimentally to be necessary to achieve a complete symmetric molten zone. Most of the resultant cylindrical rods were single crystals with twins. Still needed is a suitable automatic method to control the zone length. We tried a fiber optical technique to control the zone length, but experiments showed that application of this technique to automate zone length control is unlikely to be successful.
Deformation of a floating liquid marble.
Ooi, Chin Hong; Vadivelu, Raja K; St John, James; Dao, Dzung Viet; Nguyen, Nam-Trung
A rigid spherical particle floating on a liquid is a known problem with well-defined solutions. Under the combined effect of gravity and surface tension, the rigid particle deforms the liquid surface. However, in the case of a floating soft particle such as a liquid marble, not only the liquid surface but also the particle itself deforms. In this paper, we investigate the deformation of a floating liquid marble and characterise its height as well as aspect ratio. The experimental results show that theoretical models for a rigid spherical particle suit well for small liquid marbles. Larger marbles require an oblate liquid spheroid model. We will discuss the limitations of the two models and characterise the deformation of these marbles. PMID:25882511
Development of a Vsible-Light-Active Film for Direct Solar Energy Storage
NASA Astrophysics Data System (ADS)
Salazar, Audrey
We conceived of a two-compartment photocatalytic assembly for direct storage of solar energy as chemical potential. Our approach was to maintain reductant and oxidant in separate compartments and develop a visible light (wavelength >400nm) photo-active film to effect an uphill photoreaction between compartments. A proton exchange membrane was included in the assembly to complete the electrical circuit. Towards obtaining a working prototype of the assembly, we developed a freeze-drying method to adhere visible-light photoactive nanoparticles to a self- standing, non-porous and conductive indium tin oxide-polyvinylidene difluoride (ITO-PVDF) support film, developed in-house. We explored the possibility of employing an iron-rich metal oxide as the photocatalytic component of the film and several were explored utilizing the sodium tartrate-assisted photoreduction of Cr(VI) to Cr(III). Although the Fe2O3-coated TiO2 nanoparticles were active for photoreduction, the initial reaction rate was modest and was slowed by substantial deactivation, making it unsuitable as a photo-active material for the composite film. A complete, two-compartment assembly was prepared using cadmium sulfide (CdS) and preliminarily examined for the Cr(VI) probe reaction, however, no catalytic activity was observed. To identify the reason(s) for this observation, further testing of the apparatus and the composite film is required.
Unfolded protein response activation reduces secretion and extracellular aggregation of amyloidogenic immunoglobulin light chain
Cooley, Christina B.; Ryno, Lisa M.; Plate, Lars; Morgan, Gareth J.; Hulleman, John D.; Kelly, Jeffery W.; Wiseman, R. Luke
Light-chain amyloidosis (AL) is a degenerative disease characterized by the extracellular aggregation of a destabilized amyloidogenic Ig light chain (LC) secreted from a clonally expanded plasma cell. Current treatments for AL revolve around ablating the cancer plasma cell population using chemotherapy regimens. Unfortunately, this approach is limited to the ?70% of patients who do not exhibit significant organ proteotoxicity and can tolerate chemotherapy. Thus, identifying new therapeutic strategies to alleviate LC organ proteotoxicity should allow AL patients with significant cardiac and/or renal involvement to subsequently tolerate established chemotherapy treatments. Using a small-molecule screening approach, the unfolded protein response (UPR) was identified as a cellular signaling pathway whose activation selectively attenuates secretion of amyloidogenic LC, while not affecting secretion of a nonamyloidogenic LC. Activation of the UPR-associated transcription factors XBP1s and/or ATF6 in the absence of stress recapitulates the selective decrease in amyloidogenic LC secretion by remodeling the endoplasmic reticulum proteostasis network. Stress-independent activation of XBP1s, or especially ATF6, also attenuates extracellular aggregation of amyloidogenic LC into soluble aggregates. Collectively, our results show that stress-independent activation of these adaptive UPR transcription factors offers a therapeutic strategy to reduce proteotoxicity associated with LC aggregation. PMID:25157167
Role of Visible Light-Activated Photocatalyst on the Reduction of Anthrax Spore-Induced Mortality in Mice
Jyh-Hwa Kau; Der-Shan Sun; Hsin-Hsien Huang; Ming-Show Wong; Hung-Chi Lin; Hsin-Hou Chang; Stefan Bereswill
BackgroundPhotocatalysis of titanium dioxide (TiO2) substrates is primarily induced by ultraviolet light irradiation. Anion-doped TiO2 substrates were shown to exhibit photocatalytic activities under visible-light illumination, relative environmentally-friendly materials. Their anti-spore activity against Bacillus anthracis, however, remains to be investigated. We evaluated these visible-light activated photocatalysts on the reduction of anthrax spore-induced pathogenesis.Methodology\\/Principal FindingsStandard plating method was used to determine the
Dark/light modulation of ribulose bisphosphate carboxylase activity in plants from different photosynthetic categories
Vu, J.C.V.; Allen, L.H. Jr.; Bowes, G.
Ribulose bisphosphate carboxylase/oxygenase (RuBPCase) from several plants had substantially greater activity in extracts from light-exposed leaves than dark leaves, even when the extracts were incubated in vitro with saturating HCO/sub 3//sup -/ and Mg/sup 2 +/ concentrations. This occurred in Glycine max, Lycopersicon esculentum, Nicotiana tabacum, Panicum bisulcatum, and P. hylaeicum (C/sub 3/); P. maximum (C/sub 4/ phosphoenolpyruvate carboxykinase); P. milioides (C/sub 3//C/sub 4/); and Bromelia pinguin and Ananas comosus (Crassulacean acid metabolism). Little or no difference between light and dark leaf extracts of RuBPCase was observed in Triticum aestivum (C/sub 3/); P. miliaceum (C/sub 4/ NAD malic enzyme); Zea mays and Sorghum bicolor (C/sub 4/ NADP malic enzyme); Moricandia arvensis (C/sub 3//C/sub 4/); and Hydrilla verticillata (submersed aquatic macrophyte). It is concluded that, in many plants, especially Crassulacean acid metabolism and C/sub 3/ species, a large fraction of ribulose-1,5-bisphosphate carboxylase/oxygenase in the dark is in an inactivatable state that cannot respond to CO/sub 2/ and Mg/sup 2 +/ activation, but which can be converted to an activatable state upon exposure of the leaf to light. 16 references, 2 tables.
14 CFR 136.11 - Helicopter floats for over water.
Code of Federal Regulations, 2013 CFR
...2013-01-01 2013-01-01 false Helicopter floats for over water. 136.11 Section...Air Tour Safety Standards � 136.11 Helicopter floats for over water. (a) A helicopter used in commercial air tours over...
14 CFR 136.11 - Helicopter floats for over water.
Code of Federal Regulations, 2012 CFR
...2012-01-01 2012-01-01 false Helicopter floats for over water. 136.11 Section...Air Tour Safety Standards � 136.11 Helicopter floats for over water. (a) A helicopter used in commercial air tours over...
The influence of negative ionization of the air on motor activity in Syrian hamsters ( Masocricetus auratus Waterhouse) in light conditions
NASA Astrophysics Data System (ADS)
Lenkiewicz, Zofia; Dabrowska, Barbara; Schiffer, Zofia
The motor activity of Syrian hamsters ( Mesocricetus auratus Waterhouse) under the influence of negative ionization of the atmosphere applied for 10, 20 or 30 min per day was investigated. An ionizer with output of 14000 light negative ions per 1 cm3 of air was used. Studies carried out in the light phase of a 12?12 h light/dark regime revealed a relation between the reaction of the animal and the time of day at which ionization was applied. Ionization for 20 or 30 min in the light phase decreased motor activity, while 10 min of ionization increased it compared to control animals. Ionization in the dark phase gave a more distinct rise in activity than that applied in the light phase for all three durations of ionization.
Direct observation of frequency modulated transcription in single cells using light activation
Larson, Daniel R; Fritzsch, Christoph; Sun, Liang; Meng, Xiuhau; Lawrence, David S; Singer, Robert H
Single-cell analysis has revealed that transcription is dynamic and stochastic, but tools are lacking that can determine the mechanism operating at a single gene. Here we utilize single-molecule observations of RNA in fixed and living cells to develop a single-cell model of steroid-receptor mediated gene activation. We determine that steroids drive mRNA synthesis by frequency modulation of transcription. This digital behavior in single cells gives rise to the well-known analog dose response across the population. To test this model, we developed a light-activation technology to turn on a single steroid-responsive gene and follow dynamic synthesis of RNA from the activated locus. DOI: http://dx.doi.org/10.7554/eLife.00750.001 PMID:24069527
Activity patterns during food provisioning are affected by artificial light in free living great tits (Parus major).
Titulaer, Mieke; Spoelstra, Kamiel; Lange, Cynthia Y M J G; Visser, Marcel E
Artificial light may have severe ecological consequences but there is limited experimental work to assess these consequences. We carried out an experimental study on a wild population of great tits (Parus major) to assess the impact of light pollution on daily activity patterns during the chick provisioning period. Pairs that were provided with a small light outside their nest box did not alter the onset, cessation or duration of their working day. There was however a clear effect of artificial light on the feeding rate in the second half of the nestling period: when provided with artificial light females increased their feeding rate when the nestlings were between 9 and 16 days old. Artificial light is hypothesised to have affected the perceived photoperiod of either the parents or the offspring which in turn led to increased parental care. This may have negative fitness consequences for the parents, and light pollution may thus create an ecological trap for breeding birds. PMID:22624023
Visible-light-driven CO2 reduction with carbon nitride: enhancing the activity of ruthenium catalysts.
Kuriki, Ryo; Sekizawa, Keita; Ishitani, Osamu; Maeda, Kazuhiko
A heterogeneous photocatalyst system that consists of a ruthenium complex and carbon nitride (C3N4), which act as the catalytic and light-harvesting units, respectively, was developed for the reduction of CO2 into formic acid. Promoting the injection of electrons from C3N4 into the ruthenium unit as well as strengthening the electronic interactions between the two units enhanced its activity. The use of a suitable solvent further improved the performance, resulting in a turnover number of greater than 1000 and an apparent quantum yield of 5.7% at 400?nm. These are the best values that have been reported for heterogeneous photocatalysts for CO2 reduction under visible-light irradiation to date. PMID:25565575
An in vitro thermal analysis during different light-activated hydrogen peroxide bleaching
NASA Astrophysics Data System (ADS)
Kabbach, W.; Zezell, D. M.; Band�ca, M. C.; Pereira, T. M.; Andrade, M. F.
This study measured the critical temperature reaching time and also the variation of temperature in the surface of the cervical region and within the pulp chamber of human teeth submitted to dental bleaching using 35% hydrogen peroxide gel activated by three different light sources. The samples were randomly divided into 3 groups ( n = 15), according to the catalyst light source: Halogen Light (HL), High Intensity Diode Laser (DL), and Light Emmited Diode (LED). The results of temperature variation were submitted to the analysis of variance and Tukey test with p < 0.05. The temperature increase (mean value and standard deviation) inside the pulp chamber for the HL group was 6.8 � 2.8�C; for the DL group was 15.3 � 8.8�C; and for the LED group was 1.9 � 1.0�C for. The temperature variation (mean value and standard deviation) on the tooth surface, for the group irradiated with HL was 9.1 � 2.2�C; for the group irradiated with DL were 25.7 � 18.9�C; and for the group irradiated with LED were 2.6 � 1.4�C. The mean temperature increase values were significantly higher for the group irradiated with DL when compared with groups irradiated with HL and LED ( p < 0.05). When applying the inferior limits of the interval of confidence of 95%, an application time of 38.7 s was found for HL group, and 4.4 s for DL group. The LED group did not achieve the critical temperatures for pulp or the periodontal, even when irradiated for 360 s. The HL and DL light sources may be used for dental bleaching for a short period of time. The LED source did not heat the target tissues significantly within the parameters used in this study.
Preparation and evaluation of ketoprofen floating oral delivery system
A. H. El-Kamel; M. S. Sokar; S. S. Al Gamal; V. F. Naggar
A sustained release system for ketoprofen designed to increase its residence time in the stomach without contact with the mucosa was achieved through the preparation of floating microparticles by the emulsion-solvent diffusion technique. Four different ratios of Eudragit S100 (ES) with Eudragit RL (ERL) were used to form the floating microparticles. The drug retained in the floating microparticles decreased with
Performance Boundaries of Massive Floating Car Data Offloading
Fiore, Marco
Performance Boundaries of Massive Floating Car Data Offloading Silvia Ancona, Razvan Stanica, Marco Bari, Via Edoardo Orabona 4, 70126 Bari, Italy firstname.lastname@example.com Abstract--Floating Car Data nearly optimal performance under any FCD aggregation model. I. INTRODUCTION The term Floating Car Data
Floating-Point Division and Square Root Implementation using a
Draper, Jeff
Floating-Point Division and Square Root Implementation using a Taylor-Series Expansion Algorithm for floating-point (FP) arithmetic is an essential feature of modern microprocessor design. Although division, they are indispensable and becoming increasingly important in many modern applications. In this paper, a fused floating
Automatic Floating-Point to Fixed-Point Transformations
Evans, Brian L.
Automatic Floating-Point to Fixed-Point Transformations Kyungtae Han, Alex G. Olson, and Brian L processing and communication algorithms are first simulated using floating-point arithmetic and later transformed into fixed-point arithmetic to reduce implementation complexity. For the floating-point to fixed
Control of Free-Floating Humanoid Robots Through Task Prioritization
Sentis, Luis
Control of Free-Floating Humanoid Robots Through Task Prioritization Luis Sentis and Oussama Khatib involving free- floating behaviors. Recently, we presented a prioritized task- oriented control framework's body and environment. We adapt here this framework to the control of free-floating robots. Index Terms
Compact floating-gate true random number generator
Maryland at College Park, University of
Compact floating-gate true random number generator P. Xu, Y.L. Wong, T.K. Horiuchi and P.A. Abshire. Hot-electron injection is used in a floating-gate MOSFET to program the probability. Measurements show compact with less than 20 transistors. We use hot-electron injection in float- ing-gate MOSFETs
Tisseur, Francoise
NEWTON'S METHOD IN FLOATING POINT ARITHMETIC AND ITERATIVE REFINEMENT OF GENERALIZED EIGENVALUE Mathematics Vol. 22, No. 4, pp. 1038�1057 Abstract. We examine the behavior of Newton's method in floating method in floating point arithmetic, allowing for extended precision in computation of the residual
L A T E XParagraphs Floating around Figures Thomas Kneser
L A T E X�Paragraphs Floating around Figures Thomas Kneser Gesellschaft f�ur wissenschaftliche the figures, or -- from another point of view -- figures should `float' in paragraphs. This article presents the L A T E X style option FLOATFIG which can be used to set such Floating Figures as easily as L A T E
A FLOATING BODY APPROACH TO FEFFERMAN'S HYPERSURFACE MEASURE DAVID E. BARRETT Abstract. The floating body approach to affine surface area is adapted to a holomorphic context providing an alternate hypersurface measure, affine surface area, floating body. 2000 Mathematics Subject Classification: 32T15
Parameterized floating-point logarithm and exponential functions for FPGAs
Paris-Sud XI, Universit� de
Parameterized floating-point logarithm and exponential functions for FPGAs J�er�emie Detrey Florent, 2005 Abstract As FPGAs are increasingly being used for floating-point computing, the feasi- bility of a library of floating-point elementary functions for FPGAs is discussed. An initial implementation
Higham, Nicholas J.
NEWTON'S METHOD IN FLOATING POINT ARITHMETIC AND ITERATIVE REFINEMENT OF GENERALIZED EIGENVALUE PROBLEMS FRANC�OISE TISSEUR \\Lambda Abstract. We examine the behaviour of Newton's method in floating point. For added generality we give a detailed analysis of the general Newton method in floating point arithmetic
Floating-Point Division and Square Root Implementation using a
Draper, Jeff
Floating-Point Division and Square Root Implementation using a Taylor-Series Expansion Algorithm Institute Marina del Rey, CA 90292, USA {tjkwon, firstname.lastname@example.com Abstract--Hardware support for floating, they are indispensable and becoming increasingly important in many modern applications. In this paper, a fused floating
Floating Codes for Joint Information Storage in Write Asymmetric Memories
Bruck, Jehoshua (Shuki)
Floating Codes for Joint Information Storage in Write Asymmetric Memories Anxiao (Andrew) Jiang and other non-volatile memories based on floating-gate cells have become a very important family study codes, which we call floating codes, that maximize the total number of times the variables can
External Resource: Why Do Astronauts Float in Space?
NSDL National Science Digital Library
This NASA video segment explains why objects seem to float in space. Viewers learn that an apple that floats in space is really in a state of freefall. Since the whole space shuttle is also in freefall, the apple seems to float. An animation of a person i
Take-off activity and orientation of triatomines (Heteroptera: Reduviidae) in relation to the presence of artificial lights
Sebasti�n A. Minoli; Claudio R. Lazzari
We analysed the flying activity of Triatoma infestans and Rhodnius prolixus when confronted to artificial lights of different spectral quality. We found that the presence of light sources (white or ultraviolet) did not affect their spontaneous take-off rate. The comparison between species showed that R. prolixus was more prone to fly than T. infestans. Females of T. infestans initiated flight
Visible-Light Photochemical Activity of Heterostructured Core-Shell Materials Composed of Selected Ternary Titanates and Ferrites
Rohrer, Gregory S.
for materials selection in composite catalyst design. KEYWORDS: core-shell, photocatalyst, TiO2, dye degradation-light sensitization and the heterostructured materials showed enhanced reactivity for organic pollutant degradationVisible-Light Photochemical Activity of Heterostructured Core-Shell Materials Composed of Selected
Technology Transfer Automated Retrieval System (TEKTRAN)
Rubisco activase in some species like tobacco consists of only the shorter isoform. In Arabidopsis lack of the redox regulated, larger isoform results in an inability to modulate Rubisco activity in response to light intensity. However, light modulation can be observed in tobacco with characteristic...
Plants Actively Avoid State Transitions upon Changes in Light Intensity: Role of Light-Harvesting Complex II Protein Dephosphorylation in High Light1[OPEN
Suorsa, Marjaana; Rantala, Marjaana; Aro, Eva-Mari
Photosystem II (PSII) core and light-harvesting complex II (LHCII) proteins in plant chloroplasts undergo reversible phosphorylation upon changes in light intensity (being under control of redox-regulated STN7 and STN8 kinases and TAP38/PPH1 and PSII core phosphatases). Shift of plants from growth light to high light results in an increase of PSII core phosphorylation, whereas LHCII phosphorylation concomitantly decreases. Exactly the opposite takes place when plants are shifted to lower light intensity. Despite distinct changes occurring in thylakoid protein phosphorylation upon light intensity changes, the excitation balance between PSII and photosystem I remains unchanged. This differs drastically from the canonical-state transition model induced by artificial states 1 and 2 lights that concomitantly either dephosphorylate or phosphorylate, respectively, both the PSII core and LHCII phosphoproteins. Analysis of the kinase and phosphatase mutants revealed that TAP38/PPH1 phosphatase is crucial in preventing state transition upon increase in light intensity. Indeed, tap38/pph1 mutant revealed strong concomitant phosphorylation of both the PSII core and LHCII proteins upon transfer to high light, thus resembling the wild type under state 2 light. Coordinated function of thylakoid protein kinases and phosphatases is shown to secure balanced excitation energy for both photosystems by preventing state transitions upon changes in light intensity. Moreover, PROTON GRADIENT REGULATION5 (PGR5) is required for proper regulation of thylakoid protein kinases and phosphatases, and the pgr5 mutant mimics phenotypes of tap38/pph1. This shows that there is a close cooperation between the redox- and proton gradient-dependent regulatory mechanisms for proper function of the photosynthetic machinery. PMID:25902812
Plants Actively Avoid State Transitions upon Changes in Light Intensity: Role of Light-Harvesting Complex II Protein Dephosphorylation in High Light.
Mekala, Nageswara Rao; Suorsa, Marjaana; Rantala, Marjaana; Aro, Eva-Mari; Tikkanen, Mikko
Photosystem II (PSII) core and light-harvesting complex II (LHCII) proteins in plant chloroplasts undergo reversible phosphorylation upon changes in light intensity (being under control of redox-regulated STN7 and STN8 kinases and TAP38/PPH1 and PSII core phosphatases). Shift of plants from growth light to high light results in an increase of PSII core phosphorylation, whereas LHCII phosphorylation concomitantly decreases. Exactly the opposite takes place when plants are shifted to lower light intensity. Despite distinct changes occurring in thylakoid protein phosphorylation upon light intensity changes, the excitation balance between PSII and photosystem I remains unchanged. This differs drastically from the canonical-state transition model induced by artificial states 1 and 2 lights that concomitantly either dephosphorylate or phosphorylate, respectively, both the PSII core and LHCII phosphoproteins. Analysis of the kinase and phosphatase mutants revealed that TAP38/PPH1 phosphatase is crucial in preventing state transition upon increase in light intensity. Indeed, tap38/pph1 mutant revealed strong concomitant phosphorylation of both the PSII core and LHCII proteins upon transfer to high light, thus resembling the wild type under state 2 light. Coordinated function of thylakoid protein kinases and phosphatases is shown to secure balanced excitation energy for both photosystems by preventing state transitions upon changes in light intensity. Moreover, PROTON GRADIENT REGULATION5 (PGR5) is required for proper regulation of thylakoid protein kinases and phosphatases, and the pgr5 mutant mimics phenotypes of tap38/pph1. This shows that there is a close cooperation between the redox- and proton gradient-dependent regulatory mechanisms for proper function of the photosynthetic machinery. PMID:25902812
Interval Slopes as a Numerical Abstract Domain for Floating-Point Variables
NASA Astrophysics Data System (ADS)
Chapoutot, Alexandre
The design of embedded control systems is mainly done with model-based tools such as Matlab/Simulink. Numerical simulation is the central technique of development and verification of such tools. Floating-point arithmetic, which is well-known to only provide approximated results, is omnipresent in this activity. In order to validate the behaviors of numerical simulations using abstract interpretation-based static analysis, we present, theoretically and with experiments, a new partially relational abstract domain dedicated to floating-point variables. It comes from interval expansion of non-linear functions using slopes and it is able to mimic all the behaviors of the floating-point arithmetic. Hence it is adapted to prove the absence of run-time errors or to analyze the numerical precision of embedded control systems.
Visible Light Active Cu2+/TiO2 Nanocatalyst for Degradation of Dichlorvos
NASA Astrophysics Data System (ADS)
Segne, Teshome Abdo; Tirukkovalluri, Siva Rao; Challapalli, Subrahmanyam
The advantage of doping of TiO2 with copper has been utilized for enhanced degradation of pesticide under visible light irradiation. The sol-gel method has been undertaken for the synthesis of copper-doped TiO2 by varying the dopant loadings from 0.25 wt.% to 1.0 wt.% of Cu2+. The doped samples were characterized by UV-Visible Diffuse Reflectance Spectroscopy (DRS), N2 adsorption-desorption (BET), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), and Energy Dispersive Spectrometry (EDS). The photocatalytic activity of the catalyst was tested by degradation of dichlorvos under visible light illumination. The results found that 0.75 wt.% of Cu2+ doped nanocatalysts have better photo catalytic activity than the rest of percentages doped, undoped TiO2 and Degussa P25. The reduction of band gap was estimated and the influence of the process parameters on photo catalytic activity of the catalyst has been explained.
RNA self-cleavage activated by ultraviolet light-induced oxidation
Ariza-Mateos, Ascensi�n; Prieto-Vega, Samuel; D�az-Toledano, Rosa; Birk, Alex; Szeto, Hazel; Mena, Ignacio; Berzal-Herranz, Alfredo; G�mez, Jordi
A novel UV-C-light-induced ribozyme activity was discovered within the highly structured 5?-genomic regions of both Hepatitis C Virus (HCV) and the related Classic Swine Fever Virus (CSFV). Cleavage is mediated by exposure to UV-C light but not by exogenous oxygen radicals. It is also very selective, occurring at base positions HCV C79 and CSFV A45 in some molecules and at the immediately adjacent 5?-positions HCV U78 and CSFV U44 in others. Among other reaction products, the majority of biochemically active products detected contained 3?-phosphate and 5?-phosphate-end groups at the newly generated termini, along with a much lower amount of 3?-hydroxyl end group. While preservation of an E-loop RNA structure in the vicinity of the cleavage site was a requisite for HCV RNA self-cleavage, this was not the case for CSFV RNA. The short size of the reactive domains (?33?nt), which are compatible with primitive RNA motifs, and the lack of sequence homology, indicate that as-yet unidentified UV-activated ribozymes are likely to be found throughout structured RNAs, thereby providing clues to whether early RNA self-cleavage events were mediated by photosensitive RNA structures. PMID:21989404
Inhibition of smooth muscle cell proliferation by visible light-activated psoralen.
Sumpio, B E; Li, G; Deckelbaum, L I; Gasparro, F P
The present study was designed to evaluate the effect of 8-methoxypsoralen (8-MOP) activated with visible light (419 nm) on the suppression of smooth muscle cell (SMC) proliferation in vitro. We hypothesize that if visible light (VL) instead of UVA is used to photoactivate 8-MOP, cytotoxic 8-MOP-DNA cross-link formation can be minimized. Bovine aorta SMCs (2 x 10(4)/cm2) were incubated with 8-MOP (1 micrograms/mL) for 30 minutes (in the dark) and exposed to a range of VL (2 to 69 J/cm2) to determine the dose of VL that inhibits SMC proliferation with minimal toxicity. The results show that 8-MOP in combination with 2 to 12 J/cm2 VL reversibly inhibited SMC proliferation for up to 5 days after treatment. SMC viability was confirmed by trypan blue exclusion. 8-MOP in combination with 23- or 69-J/cm2 VL irreversibly inhibited SMC proliferation. In cell cycle studies, 12-J/cm2 VL was used to activate 8-MOP. A phase-specific G2 blockade that correlated temporally with recovery of SMC replication was observed. Photoadduct repair studies showed that cell proliferation rates recovered when 60% of the adducts had been removed. These results demonstrate for the first time the possibility of using VL to activate 8-MOP to inhibit cell proliferation and suggest that 8-MOP/VL photochemotherapy can be used to control SMC growth. PMID:8033334
Monolithic crystalline cladding microstructures for efficient light guiding and beam manipulation in passive and active regimes
Jia, Yuechen; Cheng, Chen; V�zquez de Aldana, Javier R.; Castillo, Gabriel R.; Rabes, Blanca del Rosal; Tan, Yang; Jaque, Daniel; Chen, Feng
Miniature laser sources with on-demand beam features are desirable devices for a broad range of photonic applications. Lasing based on direct-pump of miniaturized waveguiding active structures offers a low-cost but intriguing solution for compact light-emitting devices. In this work, we demonstrate a novel family of three dimensional (3D) photonic microstructures monolithically integrated in a Nd:YAG laser crystal wafer. They are produced by the femtosecond laser writing, capable of simultaneous light waveguiding and beam manipulation. In these guiding systems, tailoring of laser modes by both passive/active beam splitting and ring-shaped transformation are achieved by an appropriate design of refractive index patterns. Integration of graphene thin-layer as saturable absorber in the 3D laser structures allows for efficient passive Q-switching of tailored laser radiations which may enable miniature waveguiding lasers for broader applications. Our results pave a way to construct complex integrated passive and active laser circuits in dielectric crystals by using femtosecond laser written monolithic photonic chips. PMID:25100561
Apparent Absence of a Redox Requirement for Blue Light Activation of Pump Current in Broad Bean Guard Cells1
Taylor, Alison
of a plasma membrane H -ATPase. Using the patch clamp technique on broad bean (Vicia faba) guard cells weApparent Absence of a Redox Requirement for Blue Light Activation of Pump Current in Broad Bean
Enhanced visible-light photocatalytic activity of active Al?O?/g-C?N? heterojunctions synthesized via surface hydroxyl modification.
Li, Fa-Tang; Zhao, Ye; Wang, Qing; Wang, Xiao-Jing; Hao, Ying-Juan; Liu, Rui-Hong; Zhao, Dishun
Novel Al2O3/g-C3N4 heterojunction photocatalysts were fabricated through ultrasonic dispersion method. Al2O3, obtained via solution combustion, contained amorphous ingredient with lots of defect sites and was used as active component for transferring photo-induced electrons of g-C3N4. G-C3N4 was grafted surface hydroxyl groups in the presence of ammonia aqueous solution to combine with Al2O3 possessing positive charges via hydrogen bond. The XRD, SEM, element map, TEM, HRTEM, FT-IR, and XPS results indicate that these synthesized materials are two-phase hybrids of Al2O3 and g-C3N4 with interaction. The photocatalytic results for the degradation of rhodamine B (RhB) indicate that the most active heterojunction proportion is 60wt.% g-C3N4:40wt.% Al2O3, the visible light photocatalytic activity of which is 3.8 times that of a mechanical mixture. The enhanced performance is attributed to the high separation efficiency of photo-induced electrons from the LUMO of g-C3N4 injected into the defect sites of Al2O3, which is verified by photoluminescence spectroscopy (PL) and surface photovoltage (SPV) measurements. The electron paramagnetic resonance (EPR) signals and radical scavengers trapping experiments reveal holes (h(+)) and superoxide anion radical (O2(-)) are the main active species responsible for the degradation of RhB. PMID:25306536
Sink or Float. Modified Primary. Revised. Anchorage School District Elementary Science Program.
ERIC Educational Resources Information Center
Defendorf, Jean, Ed.
This publication provides information and activities for teaching about water, whether certain objects will sink or float, and process skills including observing, classifying, inferring, measuring, predicting, and collecting and interpreting data. There are 14 lessons in the unit. The first four lessons deal with the classification of objects and�
Floating and Sinking: Second Teacher Trials. Learning in Science Project (Primary). Working Paper No. 121.
ERIC Educational Resources Information Center
Biddulph, Fred; And Others
Two booklets were developed by the Learning in Science Project (primary)--LISP(P)--to help teachers adopt an approach to science teaching which would enhance children's understanding of floating and sinking; the strategy enables teachers to reconceptualize their teaching task from activity-driven, didactic teaching to conceptual-change teaching.�
Floating and Sinking: First Teacher Trials. Learning in Science Project (Primary). Working Paper No. 120.
ERIC Educational Resources Information Center
Appleton, Ken; And Others
Two booklets were developed by the Learning in Science Project (Primary)--LISP(P)--to help teachers adopt an approach to primary science teaching which would enhance children's understanding of floating and sinking. Both booklets were designed to enable teachers to reconceptualize their teaching task from activity-driven, didactic teaching to�
Active materials for automotive adaptive forward lighting Part 1: system requirements vs. material properties
NASA Astrophysics Data System (ADS)
Keefe, Andrew C.; Browne, Alan L.; Johnson, Nancy L.
Adaptive Frontlighting Systems (AFS in GM usage) improve visibility by automatically optimizing the beam pattern to accommodate road, driving and environmental conditions. By moving, modifying, and/or adding light during nighttime, inclement weather, or in sharp turns, the driver is presented with dynamic illumination not possible with static lighting systems The objective of this GM-HRL collaborative research project was to assess the potential of active materials to decrease the cost, mass, and packaging volume of current electric stepper-motor AFS designs. Solid-state active material actuators, if proved suitable for this application, could be less expensive than electric motors and have lower part count, reduced size and weight, and lower acoustic and EMF noise1. This paper documents Part 1 of the collaborative study, assessing technically mature, commercially available active materials for use as actuators. Candidate materials should reduce cost and improve AFS capabilities, such as increased angular velocity on swivel. Additional benefits to AFS resulting from active materials actuators were to be identified as well such as lower part count. In addition, several notional approaches to AFS were documented to illustrate the potential function, which is developed more fully in Part 2. Part 1 was successful in verifying the feasibility of using two active materials for AFS: shape memory alloys, and piezoelectrics. In particular, this demonstration showed that all application requirements including those on actuation speed, force, and cyclic stability to effect manipulation of the filament assembly and/or the reflector could be met by piezoelectrics (as ultrasonic motors) and SMA wire actuators.
Ultraviolet Light and Osmotic Stress: Activation of the JNK Cascade Through Multiple Growth Factor and Cytokine Receptors
Caridad Rosette; Michael Karin
Exposure of mammalian cells to ultraviolet (UV) light or high osmolarity strongly activates the c-Jun amino-terminal protein kinase (JNK) cascade, causing induction of many target genes. Exposure to UV light or osmotic shock induced clustering and internalization of cell surface receptors for epidermal growth factor (EGF), tumor necrosis factor (TNF), and interleukin-1 (IL-1). Activation of the EGF and TNF receptors
Long distance active hyperspectral sensing using high-power near-infrared supercontinuum light source.
Manninen, Albert; K��ri�inen, Teemu; Parviainen, Tomi; Buchter, Scott; Heili�, Miika; Laurila, Toni
A hyperspectral remote sensing instrument employing a novel near-infrared supercontinuum light source has been developed for active illumination and identification of targets. The supercontinuum is generated in a standard normal dispersion multi-mode fiber and has 16 W total optical output power covering 1000 nm to 2300 nm spectral range. A commercial 256-channel infrared spectrometer was used for broadband infrared detection. The feasibility of the presented hyperspectral measurement approach was investigated both indoors and in the field. Reflection spectra from several diffusive targets were successfully measured and a measurement range of 1.5 km was demonstrated. PMID:24664065
Active lighting applied to three-dimensional reconstruction of specular metallic surfaces by polarization imaging.
Morel, Olivier; Stolz, Christophe; Meriaudeau, Fabrice; Gorria, Patrick
In the field of industrial vision, the three-dimensional inspection of highly reflective metallic objects is still a delicate task. We deal with a new automated three-dimensional inspection system based on polarization analysis. We first present an extension of the shape-from-polarization method for dielectric surfaces to metallic surfaces. Then, we describe what we believe to be a new way of solving the ambiguity concerning the normal orientation with an active lighting system. Finally, applications to shape-defect detection are discussed, and the efficiency of the system to discriminate defects on specular metallic objects made by stamping and polishing is presented. PMID:16761046
Quantum Computing with Electrons Floating on Liquid
Dykman, Mark
Quantum Computing with Electrons Floating on Liquid Helium P. M. Platzman1 * and M. I. Dykman2 excited electrons from the surface. There is much interest in constructing analog quantum computers (AQC quantum computation is a more diffi- cult problem because these physical systems must consist
Daphnia (zoomed on floating blood cells)
NSDL National Science Digital Library
Katie Hale (CSUF; Biological Sciences)
These pin drops are the clearly defined blood cells of the Daphnia. We are only able to see the cells with use of a microscope. Keep in mind that the cells are not confined in any blood vessel (called an open circulatory system) and freely float throughout the body.
The Accuracy of Floating Point Summation
Nicholas J. Higham
. The usual recursive summation technique is just one of several ways of computing thesum of n floating point numbers. Five summation methods and their variations are analysed here.The accuracy of the methods is compared using rounding error analysis and numerical experiments.Four of the methods are shown to be special cases of a general class of methods, and an error
Error analysis of floating-point computation
J. H. Wilkinson
This paper consists of two main sections. In the first the bounds are derived for the rounding errors made in the fundamental floating-point arithmetic operations. In the second, these results are applied in the analysis of a number of computing techniques for the calculation of the eigenvalues of matrices. In each case thecomputed solution is expressed as the exact solution
Robust adaptive floating-point geometric predicates
Johnathan Richard Shewchuk
Fast C implementations of four geometric predicates, the 2D and 3D orientation and incircle tests, are publicly avail- able. Their inputs are ordinary single or double precision floating-point numbers. They owe their speed to two fea- tures. First, they employ new fast algorithms for arbitrary precision arithmetic that have a strong advantage over other software techniques in computations that manipulate
Adaptive floating search methods in feature selection
Petr Somol; Pavel Pudil; Jana Novovicov�; Pavel Pacl�k
Abstract A new,suboptimal,search strategy for feature selection is presented. It represents a more,sophisticated version of ��classical�� floating search algorithms (Pudil et al., 1994), attempts to remove some of their potential deficiencies and facilitates finding a solution even closer to the optimal,one. � 1999 Elsevier Science B.V. All rights reserved. Keywords: Pattern recognition; Feature selection; Search methods
A New Concept in Floating Production Systems
M. H. Patel; J. I. Montgomery; M. S. Worley
This paper describes a tandem hull floating production platform which combines the large deck space and high payload carrying advantages of a monohull vessel with some of the low wave induced motion characteristics that are typical of semisubmersible vessels. The basic features of the tandem hull platform are presented and comparisons made with the motion characteristics of various other hull
The salinity of a floating forest
Wesley Bruce
Joachim Scheven has proposed an interesting theory that the Euro-American coals have not grown in place but formed when a huge forest of floating aquatic plants was swept on shore and buried in the catastrophe of Noah's Flood. Scheven's video 1 and published material 2-5 indicates that the Lepidendron and Sigillaria species of the Carbon- iferous coals were aquatic plants.
End connector for floating oil boom
An end connector for joining with a similar connector to connect two fence sections of a floating oil boom is designed having a central channel and wing so that the wing of one connector is received within the channel of another connector and shoulders to allow for longitudinal movement only, a lock pin movable within a first slot into and
Submerged floating tunnels (SFTs) for Norwegian fjords
Per Tveit
Submerged floating tunnels (SFTs) weigh roughly the same as the surrounding water. The loads on the tunnel depend on the variation of the forces on the tunnel. The forces come from variation in traffic, current, temperature, waves, weight of water, weight of concrete, growth on the tunnel, wear of asphalt, dust and debris, relaxation of prestress and shrinkage and creep
Floating hydrometer with energy dissipating baffle
This patent describes a floating hydrometer employable for purposes of obtaining measurements of the presence of suspended solids in a fluid substance contained in a receptacle comprising: a. a probe portion operative as an instrument-bearing housing; b. an elongated tubular element having a hollow interior and at least one open end so as to enable the flow into the hollow
Performance Study of the Two-Stage Light Gas Gun for Active TIP Probes
NASA Astrophysics Data System (ADS)
Kim, H.; Jarboe, T. R.; Mattick, A. T.; Smith, R. J.
The Transient Internal Probe (TIP) is a diagnostic for measuring local parameters across a cord of a plasma using a refractory-clad probe that traverses the plasma at a speed of 1.8 km/sec, fast enough that heating of the probe will not cause significant ablation during transit. To date, TIP has used passive magneto-optic probes illuminated during transit by a polarized laser, and having a retroreflector to return light to an ellipsometer after a double-pass through the probe. One component of the local magnetic fields is deduced by Faraday rotation of the return light. Electro-optic probes have also been studied. A richer set of parameters, potentially including plasma temperature and density, would be afforded by active TIP probes, using on-board microelectronic sensors; information would be encoded by modulation of radiation generated on-board (i.e., LED or laser diode). This approach also avoids distortion of signals from passive probes created by stress-induced polarization effects. At issue is the survivability of on-board microelectronics under acceleration of the probe by a two-stage light-gas gun. This paper describes analytical and experimental studies of acceleration of TIP probes versus gun operating parameters. The results will be used to determine optimal gun parameters for minimizing acceleration stress, while still reaching the needed probe speeds of 1.6-1.8 km/sec.
Photogelling colloidal dispersions based on light-activated assembly of nanoparticles.
Sun, Kunshan; Kumar, Rakesh; Falvey, Daniel E; Raghavan, Srinivasa R
Photorheological (PR) fluids, i.e., fluids whose rheology can be tuned by light, have been a recent focus for our laboratory. We are interested in low-cost approaches to PR fluids using molecules or materials that are readily available. Toward this end, we report a new concept for such fluids based on light-activated assembly of nanoparticles into a physical network (gel). Our system consists of disk-like nanoparticles of laponite along with a surfactant stabilizer (Pluronic F127) and the photoacid generator (PAG), diphenyliodonium-2-carboxylate monohydrate. Initially, the nanoparticles are sterically stabilized by the surfactant, and the result is a stable, low-viscosity dispersion. Upon UV irradiation, the PAG gets photolyzed, lowering the pH by approximately 3 units. In turn, the stabilizing surfactant is displaced from the negatively charged faces of the nanoparticle disks while the edges of the disks become positively charged. The particles are thereby induced to assemble into a three-dimensional "house-of-cards" network that extends through the sample volume. The net result is a light-induced sol to gel transition, i.e., from a low, water-like viscosity to an infinite viscosity and yield stress. The yield stress of the photogel is sufficiently high to support the weight of small objects. The gel can be converted back to a sol by increasing either the pH or the surfactant content. PMID:19405469
Secure Identification of Free-Floating Planets
Cheongho Han
Among the methods proposed to detect extrasolar planets, microlensing is the only technique that can detect free-floating planets. Free-floating planets are detected through the channel of short-duration isolated lensing events. However, if a seemingly isolated planetary event is detected, it is difficult to firmly conclude that the event is caused by a free-floating planet because a wide-separation planet can also produce an isolated event. There were several methods proposed to break the degeneracy between the isolated planetary events produced by the free-floating and wide-separation planets, but they are incomplete. In this paper, we show that free-floating planets can be securely identified by conducting astrometric follow-up observations of isolated events to be detected in future photometric lensing surveys by using high-precision interferometers to be operated contemporarily with the photometric surveys. The method is based on the fact that astrometric lensing effect covers much longer range of the lens-source separation than the photometric effect. We demonstrate that several astrometric follow-up observations of isolated planetary events associated with source stars brighter than $V\\sim 19$ by using the {\\it Space Interferometry Mission} with an exposure time of $\\lesssim 10 {\\rm min}$ for each observation will make it possible to measure the centroid shift induced by primaries with projected separations up to $\\sim 100 {\\rm AU}$. Therefore, the proposed method is far more complete than previously proposed methods that are flawed by the limited applicability only to planets with projected separations $\\lesssim 20 {\\rm AU}$ or planets accompanied by bright primaries.
Theoretical studies of floating-reference method for NIR blood glucose sensing
NASA Astrophysics Data System (ADS)
Shi, Zhenzhi; Yang, Yue; Zhao, Huijuan; Chen, Wenliang; Liu, Rong; Xu, Kexin
Non-invasive blood glucose monitoring using NIR light has been suffered from the variety of optical background that is mainly caused by the change of human body, such as the change of temperature, water concentration, and so on. In order to eliminate these internal influence and external interference a so called floating-reference method has been proposed to provide an internal reference. From the analysis of the diffuse reflectance spectrum, a position has been found where diffuse reflection of light is not sensitive to the glucose concentrations. Our previous work has proved the existence of reference position using diffusion equation. However, since glucose monitoring generally use the NIR light in region of 1000-2000nm, diffusion equation is not valid because of the high absorption coefficient and small source-detector separations. In this paper, steady-state high-order approximate model is used to further investigate the existence of the floating reference position in semi-infinite medium. Based on the analysis of different optical parameters on the impact of spatially resolved reflectance of light, we find that the existence of the floating-reference position is the result of the interaction of optical parameters. Comparing to the results of Monte Carlo simulation, the applicable region of diffusion approximation and higher-order approximation for the calculation of floating-reference position is discussed at the wavelength of 1000nm-1800nm, using the intralipid solution of different concentrations. The results indicate that when the reduced albedo is greater than 0.93, diffusion approximation results are more close to simulation results, otherwise the high order approximation is more applicable.
Photonic control of flexible structures---application to a free-floating parabolic membrane shell
Hui-Ru Shih; Horn-Sen Tzou; Wilbur L. Walters Jr.
In this paper, the photonic control of free-floating flexible parabolic shells using photostrictive actuators is investigated. The parabolic shell of revolution is considered to be one of the most difficult geometries among all shell and non-shell structures. Because of this, an approximate way to estimate the dynamic behavior and light-induced control forces for a photostrictive coupled parabolic shell is presented.
Vanadium (IV) inhibits calmodulin-stimulated skeletal muscle myosin light chain kinase activity.
Parra-Diaz, D; Echegoyen, L; Zot, H G; Puett, D
Vanadium, believed to be an essential trace metal, exhibits numerous biological effects. Using electron spin resonance spectroscopy, we have demonstrated that vanadyl, vanadium (IV), the predominant intracellular form of vanadate (vanadium V), binds to calmodulin in the presence of physiological concentrations of magnesium, extending earlier work which showed competitive binding of vanadyl and calcium to calmodulin. In the presence of a magnesium-containing buffer, vanadyl does not lead to calmodulin activation of the calmodulin-dependent enzyme, rabbit skeletal muscle myosin light chain kinase; in the presence of calcium, vanadyl is a potent inhibitor of the calmodulin-activated form of the kinase. Thus, vanadyl can potentially interfere with some of the intracellular actions of calcium, presumably via binding to calmodulin. This observation deserves consideration in view of the potential clinical application of vanadium treatment to mimick insulin action and lower blood glucose. PMID:7546215
High visible light activity of hydrogenated structure-engineered mixed phase titania photocatalyst
NASA Astrophysics Data System (ADS)
Ramchiary, A.; Samdarshi, S. K.
The hydrogenation induced band-edge tailing with the resultant red-shift in the absorption spectrum and the creation of oxygen vacancies have incredible impact on the functionality of the monophasic titania photocatalyst in detoxification of aqueous pollutant under solar radiation. The mixed phase titania with optimum phase ratio consistently shows high activity in UV and/or visible radiation flux due to efficient separation of photo-generated charge carriers. We demonstrate that the hydrogenation of mixed phase titania (anatase-to-rutile ratio = 0.67) shows 15 times higher photocatalytic activity in the degradation of aqueous probe pollutant under the visible light, than the non-hydrogenated Degussa P25 catalyst.
Visible light activated ion sensing using a photoacid polymer for calcium detection.
Johns, Valentine K; Patel, Parth K; Hassett, Shelly; Calvo-Marzal, Percy; Qin, Yu; Chumbimuni-Torres, Karin Y
Presented here is a sensing membrane consisting of a modified merocyanine photoacid polymer and a calcium ionophore in plasticized poly(vinyl chloride). This membrane is shown to actively exchange protons with calcium ions when switched ON after illumination at 470 nm, and the exchange can be followed by UV-vis spectroscopy. The sensing membrane shows no response in the ON state when calcium ions are absent. The limit of detection of the sensor is 5.0 � 10(-4) M with an upper detection limit of 1.0 M. Thus, we demonstrate for the first time the use of a visible light activated, lipophilic photoacid polymer in an ion-sensing membrane for calcium ions, which highly discriminates potassium, sodium, and magnesium ions. PMID:24893213
Significantly Enhanced Visible Light Photoelectrochemical Activity in TiO2 Nanowire Arrays by Nitrogen Implantation.
Wang, Gongming; Xiao, Xiangheng; Li, Wenqing; Lin, Zhaoyang; Zhao, Zipeng; Chen, Chi; Wang, Chen; Li, Yongjia; Huang, Xiaoqing; Miao, Ling; Jiang, Changzhong; Huang, Yu; Duan, Xiangfeng
Titanium oxide (TiO2) represents one of most widely studied materials for photoelectrochemical (PEC) water splitting but is severely limited by its poor efficiency in the visible light range. Here, we report a significant enhancement of visible light photoactivity in nitrogen-implanted TiO2 (N-TiO2) nanowire arrays. Our systematic studies show that a post-implantation thermal annealing treatment can selectively enrich the substitutional nitrogen dopants, which is essential for activating the nitrogen implanted TiO2 to achieve greatly enhanced visible light photoactivity. An incident photon to electron conversion efficiency (IPCE) of ?10% is achieved at 450 nm in N-TiO2 without any other cocatalyst, far exceeding that in pristine TiO2 nanowires (?0.2%). The integration of oxygen evolution reaction (OER) cocatalyst with N-TiO2 can further increase the IPCE at 450 nm to ?17% and deliver an unprecedented overall photocurrent density of 1.9 mA/cm(2), by integrating the IPCE spectrum with standard AM 1.5G solar spectrum. Systematic photoelectrochemical and electrochemical studies demonstrated that the enhanced PEC performance can be attributed to the significantly improved visible light absorption and more efficient charge separation. Our studies demonstrate the implantation approach can be used to reliably dope TiO2 to achieve the best performed N-TiO2 photoelectrodes to date and may be extended to fundamentally modify other semiconductor materials for PEC water splitting. PMID:26052643
The effects of floating mats of Azolla filiculoides Lam. and Lemna minuta Kunth on the growth of submerged macrophytes
Rachel A. Janes; John W. Eaton; Keith Hardwick
In laboratory experiments, the growth characteristics of the submerged species Elodea nuttallii (Planch.) St. John and Potamogeton crispus L. were assessed in the presence and absence of floating mats of Azolla filiculoides Lam. and Lemna minuta Kunth. Light penetration and the development of pH and dissolved oxygen differences were monitored. The growth of P. crispus was suppressed much more than
Observations of pigment and particle distributions in the Western North Atlantic from an autonomous float and ocean color satellite
Boss, Emmanuel S.
1 Observations of pigment and particle distributions in the Western North Atlantic from, and depth and seasonal patterns associated with an increase in pigmentation per particle at low light such event in the float's record. This eddy was associated with weakly elevated surface pigment
A toolbox of Cre-dependent optogenetic transgenic mice for light-induced activation and silencing
Madisen, Linda; Mao, Tianyi; Koch, Henner; Zhuo, Jia-min; Berenyi, Antal; Fujisawa, Shigeyoshi; Hsu, Yun-Wei A.; Garcia, Alfredo J.; Gu, Xuan; Zanella, Sebastien; Kidney, Jolene; Gu, Hong; Mao, Yimei; Hooks, Bryan M.; Boyden, Edward S.; Buzs�ki, Gy�rgy; Ramirez, Jan Marino; Jones, Allan R.; Svoboda, Karel; Han, Xue; Turner, Eric E.; Zeng, Hongkui
Cell-type-specific expression of optogenetic molecules allows temporally precise manipulation of targeted neuronal activity. Here we present a toolbox of 4 knock-in mouse lines engineered for strong, Cre-dependent expression of channelrhodopsins ChR2-tdTomato and ChR2-EYFP, halorhodopsin eNpHR3.0, and archaerhodopsin Arch-ER2. All 4 transgenes mediate Cre-dependent, robust activation or silencing of cortical pyramidal neurons in vitro and in vivo upon light stimulation, with ChR2-EYFP and Arch-ER2 demonstrating light sensitivity approaching that of in utero or virally transduced neurons. We further show specific photoactivation of parvalbumin-positive interneurons in behaving ChR2-EYFP reporter mice. The robust, consistent, and inducible nature of our ChR2 mice represents a significant advancement over previous lines, whereas the Arch-ER2 and eNpHR3.0 mice are the first demonstration of successful conditional transgenic optogenetic silencing. When combined with the hundreds of available Cre-driver lines, this optimized toolbox of reporter mice will enable widespread investigations of neural circuit function with unprecedented reliability and accuracy. PMID:22446880
Reflection of light: a teaching and learning activity with primary school children
NASA Astrophysics Data System (ADS)
Varela, Paulo; Abreu, C�tia; Costa, Manuel F. M.
Light and its properties is a subject that strongly attracts children from very early ages. Inquiry-based science teaching although addressed in the curricula of various countries and suggested by some international organizations, continues to have a very low expression in the teaching practices of the majority of primary school teachers and preschool educators. In this sense, we have organized several continuing training courses in order to encourage these education professionals to promote this approach to science teaching in the classroom, with the children. As part of this training process, teachers and educators put into practice, with their students, the didactic knowledge they have developed, in order to become aware of the virtues of an inquiry-based approach to children's learning. Through the implementation of the "Reflection of Light" activity, in this article, we intend to analyze the process of teaching and learning promoted in a 3rd grade class by one of the teachers participating in the training courses. The analysis of the process reveals that the teacher in training carried out a successful didactic integration of the inquiry-based science teaching approach recommended for children. In turn, the children also developed a good understanding of the contents of the activity explored in the classroom.
Enhanced visible light photocatalytic activity of sulfated CuO-Bi2O3 photocatalyst
NASA Astrophysics Data System (ADS)
Liu, Xinlu; Zeng, Jun; Zhong, Junbo; Li, Jianzhang
Sulfate (SO4 2-)-modified CuO-Bi2O3 composite photocatalysts with different loadings of SO4 2- were prepared by a facile pore impregnating method using ammonium persulfate (NH4)2S2O8 solution. The surface parameters, structure, morphology, the response ability to light, the binding energy of Bi 4f and O 1s, the hydroxyl content on the surface and the separation rate of photoinduced hole-electron pairs were characterized by Brunauer-Emmett-Teller method, X-ray diffraction, scanning electron microscopy, UV-Vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy and surface photovoltage spectroscopy, respectively. The results reveal that sulfating of CuO-Bi2O3 decreases the band gap, increases the hydroxyl content on the surface, the separation rate of photoinduced hole-electron pairs and the adsorption of Rhodamine B on the sulfated photocatalysts. The photocatalytic activity of SO4 2-/CuO-Bi2O3 for decolorization of Rhodamine B aqueous solution was evaluated. The result shows that when the molar ratio of S/Bi is 5 %, SO4 2-/CuO-Bi2O3 exhibits the best photocatalytic activity under visible light irradiation and the possible reason is discussed.
Dark/Light modulation of ribulose bisphosphate carboxylase activity in plants from different photosynthetic categories.
Vu, J C; Allen, L H; Bowes, G
Ribulose bisphosphate carboxylase/oxygenase (RuBPCase) from several plants had substantially greater activity in extracts from lightexposed leaves than dark leaves, even when the extracts were incubated in vitro with saturating HCO(3) (-) and Mg(2+) concentrations. This occurred in Glycine max, Lycopersicon esculentum, Nicotiana tabacum, Panicum bisulcatum, and P. hylaeicum (C(3)); P. maximum (C(4) phosphoenolpyruvate carboxykinase); P. milioides (C(3)/C(4)); and Bromelia pinguin and Ananas comosus (Crassulacean acid metabolism). Little or no difference between light and dark leaf extracts of RuBPCase was observed in Triticum aestivum (C(3)); P. miliaceum (C(4) NAD malic enzyme); Zea mays and Sorghum bicolor (C(4) NADP malic enzyme); Moricandia arvensis (C(3)/C(4)); and Hydrilla verticillata (submersed aquatic macrophyte). It is concluded that, in many plants, especially Crassulacean acid metabolism and C(3) species, a large fraction of ribulose-1,5-bisphosphate carboxylase/oxygenase in the dark is in an inactivatable state that cannot respond to CO(2) and Mg(2+) activation, but which can be converted to an activatable state upon exposure of the leaf to light. PMID:16663937
A System for Implanting Laboratory Mice with Light-Activated Microtransponders
Gruda, Maryann C; Pinto, Amanda; Craelius, Aaron; Davidowitz, Hanan; Kopacka, Wesley M; Li, Ji; Qian, Jay; Rodriguez, Efrain; Kuspiel, Edward; Mandecki, Wlodek
The mouse is the most commonly used laboratory animal, accounting for up to 80% of all mammals used in research studies. Because rodents generally are group-housed, an efficient system of uniquely identifying individual animals for use in research studies, breeding, and proper colony management is required. Several temporary and permanent methods (for example, ear punching and toe clipping) are available for labeling research mice and other small animals, each with advantages and disadvantages. This report describes a new radiofrequency identification tagging method that uses 500-�m, light-activated microtransponders implanted subcutaneously into the ear or tail of mice. The preferred location for implanting is in the side of the tail, because implantation at this site was simple to perform and was associated with shorter implantation times (average, 53 versus 325 s) and a higher success rate (98% versus 50%) compared with the ear. The main benefits of using light-activated microtransponders over other identification methods, including other radiofrequency identification tags, is their small size, which minimizes stress to the animals during implantation and low cost due to their one-piece (monolithic) design. In addition, the implantation procedure uses a custom-designed 21-gauge needle injector and does not require anesthetization of the mice. We conclude that this method allows improved identification and management of laboratory mice. PMID:21205448
Structural details of light activation of the LOV2-based photoswitch PA-Rac1.
Winkler, Andreas; Barends, Thomas R M; Udvarhelyi, Anik�; Lenherr-Frey, Daniel; Lomb, Lukas; Menzel, Andreas; Schlichting, Ilme
Optical control of cellular processes is an emerging approach for studying biological systems, affording control with high spatial and temporal resolution. Specifically designed artificial photoswitches add an interesting extension to naturally occurring light-regulated functionalities. However, despite a great deal of structural information, the generation of new tools cannot be based fully on rational design yet; in many cases design is limited by our understanding of molecular details of light activation and signal transduction. Our biochemical and biophysical studies on the established optogenetic tool PA-Rac1, the photoactivatable small GTPase Rac1, reveal how unexpected details of the sensor-effector interface, such as metal coordination, significantly affect functionally important structural elements of this photoswitch. Together with solution scattering experiments, our results favor differences in the population of pre-existing conformations as the underlying allosteric activation mechanism of PA-Rac1, rather than the assumed release of the Rac1 domain from the caging photoreceptor domain. These results have implications for the design of new optogenetic tools and highlight the importance of including molecular details of the sensor-effector interface, which is however difficult to assess during the initial design of novel artificial photoswitches. PMID:25368973
Fluorescent light activates the immunomodulator cis-urocanic acid in vitro: implications for patients with systemic lupus erythematosus.
McGrath, H; Bell, J M; Haycock, J W
OBJECTIVE--Erythemagenic (295-305 nm) ultraviolet-B (UVB) radiation is toxic to patients with systemic lupus erythematosus (SLE). Cool white fluorescent lamp emissions produce a similar toxicity even though the UVB radiation emitted is primarily at the relatively non-erythemagenic wavelength of 313 nm. The purpose of this study was to determine if fluorescent light, presumably acting predominantly along the 313 nm wavelength, exhibits photochemical activity sufficient to account for toxicity. METHODS--The photochemical activity of fluorescent light was assessed by testing its capacity to activate urocanic acid, a plentiful and potent epidermal immunological mediator normally activated by polychromatic UVB radiation but activated maximally at 313 nm. Irradiation-induced isomerisation of trans-urocanic to cis-urocanic acid was quantitated by UV spectroscopy after separation of the isomers by high performance liquid chromatography. RESULTS--Fluorescent light irradiation of solutions containing the photoreceptor trans-urocanic acid produced a cumulative conversion of trans-to-cis-urocanic acid. This photochemical activity was compared with that of erythemagenic sunlamps, high in polychromatic UVB emissions. When normalised for UVB irradiance, the accumulation of cis-urocanic acid produced by both light sources was essentially equivalent. Conventional acrylic diffusers that absorb UVB emissions eliminated the fluorescent light-induced reaction. CONCLUSION--The results indicate that radiation from fluorescent lamps possesses substantial photoimmunological capability, sufficient to activate a potent, potentially dangerous, disease-modifying, immunomodulatory pathway and that poorly erythemagenic, primarily monochromatic UVB photons are responsible. PMID:8037497
Light activated, In situ Forming Gel for Sustained Suprachoroidal Delivery of Bevacizumab
Tyagi, Puneet; Barros, Matthew; Stansbury, Jeffrey W.; Kompella, Uday B.
Purpose To develop a light activated polycaprolactone dimethacrylate and hydroxyethyl methacrylate based gel network that sustains the release of stable, active bevacizumab (an anti-VEGF antibody used to treat choroidal neovascularization) and to assess sustained ex vivo delivery in rabbit eyes and in vivo delivery in rat eyes following in situ gel formation in the suprachoroidal space. Methods Polycaprolactone dimethacrylate (PCM) was synthesized from polycaprolactone diol (PCD) and evaluated using NMR spectroscopy. PCM was used to cross-link hydroxyethyl methacrylate (HEMA) in the presence of 365 nm UV light and 2, 2-dimethoxy-2-phenylacetophenone (DMPA) as a photoinitiator. Bevacizumab was entrapped in the gel using 3 different cross-linking durations of 3, 7, and 10 minutes. In vitro release of bevacizumab in PBS pH 7.4 at 37�C during a 4 months study was quantified using a VEGF-binding based ELISA. Stability of released bevacizumab was monitored by size exclusion chromatography (SEC) and circular dichroism. Alexa Fluor� 488 dye conjugated bevacizumab mixed with polymers was injected suprachoroidally in rabbit eyes to study the effect of different cross-linking durations on the spread of the dye conjugated bevacizumab. In vivo delivery was assessed in Sprague Dawley (SD) rats by injecting Alexa Fluor� 488 dye conjugated bevacizumab mixed with polymers followed by cross-linking for 10 minutes. Spread in the rabbit eyes and in vivo delivery in rat eyes was monitored noninvasively using a fundus camera and Fluorotron Master�. Results Formation of PCM was confirmed by the disappearance of hydroxyl peak in NMR spectra. Cross-linking duration of 10 minutes resulted in a burst release of 21 % of bevacizumab. Other cross-linking durations had ? 62 % burst release. Bevacizumab release from 10 minute cross-linked gel was sustained for ? 4 months. Release samples contained ? 96.1 % of bevacizumab in the monomeric form as observed in SEC chromatograms. Circular dichroism confirmed that secondary ?-sheet structure of bevacizumab was maintained after release from the gel. As the cross-linking duration was increased to 10 minutes, the gel/antibody was better confined at the injection site in excised rabbit eye suprachoroidal space. Delivery of Alexa Fluor� 488 dye conjugated bevacizumab was sustained for at least 60 days in the suprachoroidal space of SD rats. Conclusion PCM and HEMA gel sustained bevacizumab release for 4 months and maintained the stability and VEGF-binding activity of bevacizumab. Light activated PCM and HEMA gel is suitable for in situ gel formation and sustained protein delivery in the suprachoroidal space. PMID:23734705
Influence of light-activation protocol on methacrylate resin-composite evaluated by dynamic mechanical analysis and degree of conversion.
Giorgi, Maria Cec�lia C; Pistor, Vin�cius; Mauler, Raquel S; Lima, D�bora A N L; Marchi, Giselle M; Aguiar, Fl�vio H B
The aim of this study was to evaluate the degree of conversion (DC) and to identify the viscoelastic properties: storage modulus (E'), loss modulus (E"), tangent delta (tan ?), and glass transition temperature (T g ) of a microhybrid resin-composite light-activated by three different protocols. A Filtek Z250 (3 M ESPE) shade A3 was inserted in a Teflon mold (21 mm?�?5 mm?�?1 mm for viscoelastic properties; and 5 mm?�?1 mm for DC) and light-activated according to the following light-activation protocols: (S) 1,000 mW/cm(2)?�?19 s, (HP) 1,400 mW/cm(2)?�?14 s, and (PE) 3,200 mW/cm(2)?�?6 s, all set up to deliver 19 J/cm(2). Viscoelastic properties was assessed by dynamic mechanical analysis (DMA) (n?=?3), performed in single cantilever clamped mode. DC (n?=?5) was measured by FTIR on top (T) and bottom (B) surfaces, and the data was submitted to a split-plot one-way ANOVA. For DC, there was a significant effect for surface factor and light-activation protocols factor. Top surface showed higher DC than B in all experimental conditions. Light-activation protocols S and HP resulted in higher DC than PE and were similar between them. Viscoelastic properties (E', E", tan ?, T g ) were not affected by light-activation protocols. It could be concluded that light-activation protocols influenced DC but not influenced the viscoelastic properties. PMID:24740520
Bismuth titanate pyrochlore microspheres: Directed synthesis and their visible light photocatalytic activity
Hou, Jungang, E-mail: email@example.com [School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Jiao, Shuqiang; Zhu, Hongmin [School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Kumar, R.V. [Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB2 3QZ (United Kingdom)
Bismuth titanates, Bi{sub 2}Ti{sub 2}O{sub 7} (BIT), with well-defined spherical structures were synthesized by a facile hydrothermal process without the use of any surfactant or template. XRD and SEM studies have shown that spheres could be fabricated in high yields by simply manipulating the concentrations of hydroxide ions. In this case, hydroxide ions seem to play a pivotal role in controlling the formation of seeds and growth rates of the BIT particles. On the basis of structural analysis of samples obtained at different concentrations of OH{sup -}, we also proposed a plausible mechanism to account for the formation of these distinctive morphologies under different conditions. The as-prepared BIT microspheres with good stability exhibited higher photocatalytic activities in the degradation of Rhodamine B (RhB) under visible light irradiation than that in commercial P25 TiO{sub 2}. Furthermore, the enhanced photocatalytic performance for RhB degradation was also investigated with assistance of a small amount of H{sub 2}O{sub 2}. -- Graphical abstract: Bismuth titanate pyrochlore microspheres were synthesized by a facile hydrothermal process without the use of any surfactant or template, and the effects of concentration of OH{sup -} on the diameter of microspheres, growth mechanism and photocatalytic properties were investigated. Display Omitted Research Highlights: Bismuth titanate pyrochlore microspheres with different diameters were synthesized by a facile hydrothermal process without the use of any surfactant or template. The BIT microspheres with good stability exhibited higher photocatalytic activities in the degradation of RhB under visible light irradiation than that in commercial P25 TiO{sub 2}. Further enhanced photocatalytic activity for RhB degradation was ascribed to the assistance of a small amount of H{sub 2}O{sub 2}.
Towards an electronic nose based on nano-structured transition metal oxides activated by a tuneable UV light source
Bonex Wakufwa Mwakikunga; Thomas Malwela; Kenneth Thembela Hillie; Gebhu Ndlovu
Traditional gas sensors involve heating the sensor material for gas selectivity. New gas approaches require activation by a broadband UV light source. We propose to employ a tuneable UV source in which this source is tuned for its many wavelengths via a grating and associated optics and transducers. The theory of UV activated gas sensing is presented and the first
The difference between ``giving a rose'' and ``giving a kiss'': Sustained neural activity to the light verb construction
Kuperberg, Gina
The difference between ``giving a rose'' and ``giving a kiss'': Sustained neural activity associated with processing light verb constructions such as ``give a kiss''. These construc- tions consist and also activates an argument structure of its own (``kiss''). This creates a mismatch between
The difference between "giving a rose" and "giving a kiss": Sustained neural activity to the light verb construction
Kuperberg, Gina
1 The difference between "giving a rose" and "giving a kiss": Sustained neural activity associated with processing light verb constructions such as "give a kiss". These constructions consist and also activates an argument structure of its own ("kiss"), which creates a mismatch between
Light-activated protein inhibition through photoinduced electron transfer of a ruthenium(II)-cobalt(III) bimetallic complex.
Holbrook, Robert J; Weinberg, David J; Peterson, Mark D; Weiss, Emily A; Meade, Thomas J
We describe a mechanism of light activation that initiates protein inhibitory action of a biologically inert Co(III) Schiff base (Co(III)-sb) complex. Photoinduced electron transfer (PET) occurs from a Ru(II) bipyridal complex to a covalently attached Co(III) complex and is gated by conformational changes that occur in tens of nanoseconds. Reduction of the Co(III)-sb by PET initiates displacement of the inert axial imidazole ligands, promoting coordination to active site histidines of ?-thrombin. Upon exposure to 455 nm light, the rate of ligand exchange with 4-methylimidazole, a histidine mimic, increases by approximately 5-fold, as observed by NMR spectroscopy. Similarly, the rate of ?-thrombin inhibition increases over 5-fold upon irradiation. These results convey a strategy for light activation of inorganic therapeutic agents through PET utilizing redox-active metal centers. PMID:25671465
Light-Activated Protein Inhibition through Photoinduced Electron Transfer of a Ruthenium(II)�Cobalt(III) Bimetallic Complex
Holbrook, Robert J.; Weinberg, David J.; Peterson, Mark D.; Weiss, Emily A.; Meade, Thomas J.
We describe a mechanism of light activation that initiates protein inhibitory action of a biologically inert Co(III) Schiff base (Co(III)-sb) complex. Photoinduced electron transfer (PET) occurs from a Ru(II) bipyridal complex to a covalently attached Co(III) complex and is gated by conformational changes that occur in tens of nanoseconds. Reduction of the Co(III)-sb by PET initiates displacement of the inert axial imidazole ligands, promoting coordination to active site histidines of ?-thrombin. Upon exposure to 455 nm light, the rate of ligand exchange with 4-methylimidazole, a histidine mimic, increases by approximately 5-fold, as observed by NMR spectroscopy. Similarly, the rate of ?-thrombin inhibition increases over 5-fold upon irradiation. These results convey a strategy for light activation of inorganic therapeutic agents through PET utilizing redox-active metal centers. PMID:25671465
Comparison of light, food, and temperature as environmental synchronizers of the circadian rhythm of activity in mice.
Refinetti, Roberto
Although entrainment (and masking) of circadian rhythms by light has been extensively studied, much less attention has been given to other environmental cycles that can modulate circadian rhythms in mammals. In this study in mice, the entraining strength of different environmental cycles was compared. Running-wheel activity was monitored before, after, and while the animals were under one of four environmental cycles: a full light-dark cycle with 12�h of light and 12�h of darkness each day, a cycle of 1�h of light per day, a cycle of food availability consisting of 80�% of the baseline free-feeding amount presented once a day, and an ambient temperature cycle consisting of 23�h at 24��C and 1�h at 12��C each day. Four measures of zeitgeber strength were used: percentage of animals that entrained, rhythm robustness in the entrained state, stability of activity onsets, and stability of acrophases. The results indicate that, at least in mice, a full light-dark cycle is the most powerful modulator of the circadian rhythm of locomotor activity, as a consequence of both entrainment and masking. When entrainment alone is considered, temperature seems to be as strong a modulator as light, while food restriction is a weaker modulator and affects primarily a food-anticipatory component of the activity rhythm. PMID:25800223
Eye-independent, light-activated chromatophore expansion (LACE) and expression of phototransduction genes in the skin of Octopus bimaculoides.
Ramirez, M Desmond; Oakley, Todd H
Cephalopods are renowned for changing the color and pattern of their skin for both camouflage and communication. Yet, we do not fully understand how cephalopods control the pigmented chromatophore organs in their skin and change their body pattern. Although these changes primarily rely on eyesight, we found that light causes chromatophores to expand in excised pieces of Octopus bimaculoides skin. We call this behavior light-activated chromatophore expansion (or LACE). To uncover how octopus skin senses light, we used antibodies against r-opsin phototransduction proteins to identify sensory neurons that express r-opsin in the skin. We hypothesized that octopus LACE relies on the same r-opsin phototransduction cascade found in octopus eyes. By creating an action spectrum for the latency to LACE, we found that LACE occurred most quickly in response to blue light. We fit our action spectrum data to a standard opsin curve template and estimated the ?max of LACE to be 480?nm. Consistent with our hypothesis, the maximum sensitivity of the light sensors underlying LACE closely matches the known spectral sensitivity of opsin from octopus eyes. LACE in isolated preparations suggests that octopus skin is intrinsically light sensitive and that this dispersed light sense might contribute to their unique and novel patterning abilities. Finally, our data suggest that a common molecular mechanism for light detection in eyes may have been co-opted for light sensing in octopus skin and then used for LACE. PMID:25994633
Investigations of riboflavin photolysis via coloured light in the nitro blue tetrazolium assay for superoxide dismutase activity.
Cheng, Chien-Wei; Chen, Liang-Y�; Chou, Chan-Wei; Liang, Ji-Yuan
Determination of the superoxide dismutase activity is an important issue in the fields of biochemistry and the medical sciences. In the riboflavin/nitro blue tetrazolium (B2/NBT) method, the light sources used for generating superoxide anion radicals from light-excited riboflavin are normally fluorescent lamps. However, the conditions of B2/NBT experiments vary. This study investigated the effect of the light source on the light-excitation of riboflavin. The effectiveness of the photolysis was controlled by the wavelength of the light source. The spectra of fluorescent lamps are composed of multiple colour lights, and the emission spectra of fluorescent lamps made by different manufacturers may vary. Blue light was determined to be the most efficient for the photochemical reaction of riboflavin in visible region. The quality of the blue light in fluorescent lamps is critical to the photo-decomposition of riboflavin. A blue light is better than a fluorescent lamp for the photo-decomposition of riboflavin. The performance of the B2/NBT method is thereby optimized. PMID:25985146
Behavioral Masking and cFos Responses to Light in Day- and Night-Active Grass Rats.
Langel, Jennifer; Yan, Lily; Nunez, Antonio A; Smale, Laura
Light not only entrains the circadian system but also has acute effects on physiology and behavior, a phenomenon known as masking. Behavioral masking responses to bright light differ in diurnal and nocturnal species, such that light increases arousal in the former and decreases it in the latter. Comparisons made within a species that displays both diurnal and nocturnal patterns of behavior may provide insight into how masking differs between chronotypes and the association between mechanisms controlling masking and the circadian drive for activity. Nile grass rats (Arvicanthis niloticus) provide a useful model for studying such issues because when these animals are housed with running wheels, some run primarily during day, while others run at night. Here we compared behavioral masking responses to 2-h pulses of light and darkness given across a 12:12 light/dark cycle in day-active (DA) and night-active (NA) grass rats. Both wheel-running activity (WRA) and general activity (GA) were monitored. Light pulses at night tended to increase both WRA and GA overall in the DA grass rats, while in NA grass rats, light pulses significantly reduced WRA but had no effect on GA. Dark pulses during the day tended to decrease both WRA and GA in the DA grass rats, while in the NA grass rats, they tended to increase WRA in the early day but had no effect on GA overall. Next, we measured cFos expression within 2 brain areas potentially involved in masking, the intergeniculate leaflet (IGL) and the olivary pretectal area (OPT), of DA and NA grass rats either sacrificed on a control night or after a 1-h light pulse at ZT14. In DA grass rats, light at ZT14 induced cFos in the IGL and OPT, whereas in NA grass rats, cFos levels in both structures were high at ZT14 and were not altered by a 1-h light pulse. Overall, these results suggest that masking responses to light and darkness are dependent on the chronotype of the individual and that the responsiveness of the IGL and OPT to light may depend on or contribute to the behavioral response of these animals. PMID:24916392
A new concept in floating production systems
Patel, M.H.; Montgomery, J.I.; Worley, M.S.
This paper describes a tandem hull floating production platform which combines the large deck space and high payload carrying advantages of a monohull vessel with some of the low wave induced motion characteristics that are typical of semisubmersible vessels. The basic features of the tandem hull platform are presented and comparisons made with the motion characteristics of various other hull forms. The model tests and computer simulation programs used in the design of the tandem hull platform are described and the results presented. Assessments are made of the capital and operating costs of a tandem hull production system and comparisons made with those of other floating production systems that are based on alternative hull forms.
Computer-controlled float zone crystal growth
NASA Technical Reports Server (NTRS)
Chan, Y. T.; Mailloux, P. A.
A PC-based computer control system to automate a high-temperature float zone growth of titanium carbide is reported. The control strategy of the computer control system relies on the relations derived from a combination of empirical relations and results from detailed mathematical analysis of the physical transports of the entire float zone assembly. A system control computer program was written to establish real-time determination of the size of the molten zone from a thermal image, control parameters from established relationships, and collected processed data to achieve control objectives. We found that the developed computer control allows the growth process to be operated nearer the stability limit. Any slight variations in growth conditions can be corrected in time to avoid any instability growth, which otherwise cannot be adjusted via manual control.
Mesoporous zinc ferrite: synthesis, characterization, and photocatalytic activity with H2O2/visible light.
Su, Minhua; He, Chun; Sharma, Virender K; Abou Asi, Mudar; Xia, Dehua; Li, Xiang-zhong; Deng, Huiqi; Xiong, Ya
Mesoporous ZnFe(2)O(4) (meso-ZnFe(2)O(4)) was synthesized by a hydrothermal process in which cetyltrimethylammonium bromide (CTAB) participates in the reaction to produce nanocrystals. Synthesized ZnFe(2)O(4) was characterized by energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area, scanning electronic microscopy (SEM), transmission electron microscopy (TEM), and diffuse reflectance spectra (DRS). The meso-ZnFe(2)O(4) was resulted from the agglomeration of nanoparticles with size of 5-10nm. The photocatalytic activity of ZnFe(2)O(4) under visible light (?>400 nm) was evaluated by the degradation of Acid Orange II (AOII) at different sintering temperatures, the amount of ZnFe(2)O(4), and the concentration of H(2)O(2). The photocatalytic degradation of AOII was almost complete within 2h in H(2)O(2)/visible light system. The high efficiency for AOII degradation was attributed to the strong absorption of ZnFe(2)O(4) in visible-light region and the generation of reactive OH by H(2)O(2) in the system. The involvement of OH in oxidizing AOII was examined by determining the photocurrent of ZnFe(2)O(4), [OH], and degradation rates using different scavengers. Organic compounds as intermediates of the degradation process were identified by LC/MS. Moreover, ZnFe(2)O(4) retained their degradation efficiencies for a series of repetitive batch runs, indicating the true photocatalytic process. PMID:22018870
Zooplankton response to shading effects of free-floating plants in shallow warm temperate lakes: a field mesocosm experiment
M. S. Fontanarrosa; G. Chaparro; P. de Tezanos Pinto; P. Rodriguez; I. O�Farrell
Dense mats of free floating plants (FFP) often produce severe underwater light attenuation and strong oxygen depletion in\\u000a the water column. In this study, we experimentally assessed the zooplankton response to artificial shading using field mesocosms.\\u000a During 30 days, we simulated three different light scenarios by mimicking the persistence, absence, and fluctuation of FFP\\u000a typically encountered in vegetated shallow subtropical
Floating and fixed artificial habitats: Spatial and temporal patterns of benthic communities in a coral reef environment
NASA Astrophysics Data System (ADS)
Perkol-Finkel, S.; Zilman, G.; Sella, I.; Miloh, T.; Benayahu, Y.
While natural marine habitats with motion capabilities, e.g., kelps and seaweeds, have been studied alongside their associated fouling communities, little is known of the effect of motion on the communities of floating artificial habitats such as buoys, rafts, and pontoons, particularly in tropical systems. Hydrodynamic features greatly differ between floating and fixed artificial substrata, which in turn affect the structure of their associated communities. This study tested the hypothesis that floating and fixed artificial installations in a tropical reef system (Eilat, Red Sea) would support different benthic communities throughout space and time. Specifically, we examined differences in communities recruited onto settlement plates between floating and fixed installations deployed at three different sites, along a two-year monitoring period. The three sites exhibited distinct differences in species assemblages between the monitoring dates (6, 12, 18 and 24 months post deployment), mainly between the first and the last two dates. The average level of dissimilarity between floating and fixed installations increased over time at all sites. Over 50% of the dissimilarity between the floating and fixed installations resulted from five taxonomic groups i.e., bryozoans, bivalves, barnacles, sponges, including the amount of bare space on the settlement plates. The contribution of these groups to the dissimilarity changed both temporally within each site, and spatially among sites. The observed differences were related to the hydrodynamic characteristics of floating and fixed habitats, interacting with biotic features such as predation, successional processes and seasonality; and abiotic features including small-scale spatial changes, light, and position in the water column.
An Autozeroing Floating-Gate Amplifier
Paul Hasler; Bradley A. Minch; Chris Diorio
We have developed a bandpass floating-gate amplifier that uses tunneling and pFET hot-electron injection to set its dc operating point adaptively. Because the hot-electron injection is an inherent part of the pFET's behavior, we obtain this adaptation with no additional circuitry. Because the gate currents are small, the circuit exhibits a high-pass characteristic with a cutoff frequency less than 1
Free-floating atmospheric pressure ball plasmas
G. A. Wurden; C. Ticos; Z. Wang; C. J. V. Wurden
A long-lived (0.3 second, 10-20 cm diameter) ball plasma floating in the air above a water surface has been formed and studied in the laboratory. A 0.4 - 1 mF capacitor is charged to 4-5 kV, and subsequently discharged (30-60 Amps, 20-50 msec duration) into central copper cathode held fixed just below the surface of a bucket of water (with
Fast Decimal Floating-Point Division
Hooman Nikmehr; Braden Phillips; Cheng-chew Lim
Abstract�A new implementation for decimal floating-point (DFP) division is introduced. The algorithm is based on high-radix SRT division, with the recurrence in a new decimal signed-digit format. Quotient digits are selected using comparison multiples, where the magnitude of the quotient digit is calculated by comparing the truncated partial remainder with limited precision multiples of the divisor. The sign is determined
Floating Ice: Grades K-1: Electronic Book
NSDL National Science Digital Library
Jessica Fries-Gaither
This informational text discusses the unique property of ice - that it floats in liquid water. Students focus on real-world examples and how ice is necessary for life in the polar regions. The text is written at a kindergarten through grade one reading level. This is an onscreen version that contains recorded narration allowing students to listen to the text as they read along. Highlighted vocabulary words have individually recorded definitions heard by clicking on the links.
Floating Ice: Grades K-1: Illustrated Book
NSDL National Science Digital Library
Jessica Fries-Gaither
This informational text discusses the unique property of ice - that it floats in liquid water. Students focus on real-world examples and how ice is necessary for life in the polar regions. The text is written at a kindergarten through grade one reading level. This version is a full-color PDF that can be printed, cut and folded to form a book. Each book contains color photographs and illustrations.
Finite Element Analysis of a Floating Microstimulator
Sahin, Mesut; Ur-Rahman, Syed S.
Analytical solutions for voltage fields in a volume conductor are available only for ideal electrodes with radially symmetric contacts and infinitely extending substrates. Practical electrodes for neural stimulation may have asymmetric contacts and finite substrate dimensions and hence deviate from the ideal geometries. For instance, it needs to be determined if the analytical solutions are adequate for simulations of narrow shank electrodes where the substrate width is comparable to the size of the contacts. As an extension to this problem, a �floating� stimulator can be envisioned where the substrate would be finite in all directions. The question then becomes how small this floating stimulator can be made before its stimulation strength is compromised by the decrease in the medium impedance between the contacts as the contacts are approaching each other. We used finite element modeling to solve the voltage and current profiles generated by these radially asymmetric electrode geometries in a volume conductor. The simulation results suggest that both the substrate size and the bipolar contact separation influence the voltage field when these parameters are as small as a few times the contact size. Both of these effects are larger for increasing elevations from the contact surface, and even stronger for floating electrodes (finite substrate in all directions) than the shank-type electrodes. Location of the contacts on the floating electrode also plays a role in determining the voltage field. The voltage field for any device size and current, and any specific resistance of the volume conductor can be predicted from these results so long as the aspect ratios are preserved. PMID:17601192
IEEE Standard unifies arithmetic model Floating points
Beron-Vera, Francisco Javier
-point number system. Some were binary; some were decimal. There was even a Russian computer that used trinary floating-point system with only three bits each for f and e. Between 2e and 2e+1 the numbers are equally between 1 and 2 in our toy system is 2-3 , or 1 /8. In the full IEEE system, this spacing is 2-52 . MATLAB
Light illuminated ?-Fe2O3/Pt nanoparticles as water activation agent for photoelectrochemical water splitting.
Li, Xiaodong; Wang, Zhi; Zhang, Zemin; Chen, Lulu; Cheng, Jianli; Ni, Wei; Wang, Bin; Xie, Erqing
The photoelectrochemical (PEC) water splitting is hampered by strong bonds of H2O molecules and low ionic conductivity of pure water. The photocatalysts dispersed in pure water can serve as a water activation agent, which provides an alternative pathway to overcome such limitations. Here we report that the light illuminated ?-Fe2O3/Pt nanoparticles may produce a reservoir of reactive intermediates including H2O2, �OH, OH(-) and H(+) capable of promoting the pure water reduction/oxidation half-reactions at cathode and highly photocatalytic-active TiO2/In2S3/AgInS2 photoanode, respectively. Remarkable photocurrent enhancement has been obtained with ?-Fe2O3/Pt as water activation agent. The use of ?-Fe2O3/Pt to promote the reactivity of pure water represents a new paradigm for reproducible hydrogen fuel provision by PEC water splitting, allowing efficient splitting of pure water without adding of corrosive chemicals or sacrificial agent. PMID:25773684
Float pump offshore wave energy converters
Nielsen, K. [Danish Wave Power Aps, Virum (Denmark)
This paper will describe the numerical design models developed by DWP and ES-Consult as part of the Off-shore Wave Energy Converter project OWEC-1 supported by the European Union under the JOULE initiative. Offshore Wave Power Plants composed of float pump systems, has been investigated. Modeling techniques required to provide reliable methods for the predicted hydrodynamic behavior of the floats, their performance has been assessed and standardized criteria and techniques for the design has been provided. The systems investigated and the numerical time domain models developed will be described. The DWP/ES-Consult design models include both heave and surge motion of the device motion. The hydrodynamics are based on the long wave approximation of wave exiting forces as well as nonlinear drag and lift-forces, limits for the buoyancy force and variation of added mass with submergence are included in the calculations. The numerical models developed by DWP/ES-Consult are intended as tools for the structural design. The results in medium waves are compared to more exact hydrodynamic models (heave only) developed at Chalmars University and at NTH norwegian Technical University. Results are compared to model tests and real sea measurements. The design of the float geometry`s and power takeoff has not been optimized. The scope has been to compare and provide tools and guidelines for time domain modeling of offshore wave energy converters as a basis for further optimization.
Capillary induced buckling of floating sheets
NASA Astrophysics Data System (ADS)
Pineirua, Miguel; Bico, Jose; Roman, Benoit; Menon, Narayanan
When a water droplet is deposited over a thin floating sheet, radial wrinkles appear in the vicinity of the droplet as a result of capillary forces exerted at the contact line [1]. However, determining the stress state at the contact line is still challenging and limits the full description of the wrinkling pattern. In order to avoid this contact line ambiguities, we propose the experimental study of the buckling of a macroscopic annulus floating on the surface of water and submitted to a difference in surface tension between its inner and outer edges. This particular configuration allows to generate radial wrinkles on the membrane with well defined border conditions. The topography of the wrinkled patterns are precisely measured using a synthetic Schlieren technique. Based on the standard buckling theory, we develop scaling laws for the buckling threshold of the annulus as well as for the wave length and radial extension of the wrinkles, which are compared to our experimental results and numerical simulations. [4pt] [1] J. Huang, M. Juszkiewicz, W.H. de Jeu, E. Cerda, T. Emrick, N. Menon, and T.P. Russell. Capillary wrinkling of floating thin polymer films. Science, 317(5838):650-653, 2007.
FPP [Floating Potential Probe] Results, Final Report
NASA Technical Reports Server (NTRS)
Ferguson, Dale C.
The Floating Potential Probe (FPP) operated on the International Space Station (ISS) from December 2000 to April 2001. During that time, it took many measurements of the ISS floating potential and the electron density and temperature. Those measurements were used as inputs to the Environments WorkBench (EWB) model of ISS potentials (originally developed by SAIC, but now sometimes called the Boeing model) that is used even today to predict charging levels for ISS. FPP is now completely defunct, having been removed and ejected from ISS. With the advent of the new Floating Potential Monitoring Unit (FPMU) on ISS, and the beginning of ISS operations with two large solar array panels instead of just one, a review of FPP measurements can offer comparisons with the new FPMU data and perhaps improve the accuracy of future ISS charging predictions. In particular, FPP measurements during times of low electron temperature and high electron density (the times of worst ISS charging) will be brought forward for comparison with the newly obtained FPMU data.
Floating boom performance under waves and currents.
Castro, A; Iglesias, G; Carballo, R; Fraguela, J A
Floating booms constitute a fundamental tool for the protection of marine and coastal ecosystems against accidental oil spills. Their containment performances in exposed areas are often impaired by the action of waves, currents and winds in a manner which is dependent on the boom's response as a floating body, and which is not fully understood at present. In this work the relationship between the design parameters of a floating boom section and its efficiency against the mode of failure by drainage under a variety of wave and current combinations is investigated by means of physical modelling. Seven boom models with different geometries and buoyancy-weight ratios are tested with an experimental setup that allows them to have and rotate freely. The model displacements under waves (both regular and irregular) and currents, as well as those of the free surface adjacent to the model, are measured with a Computer Vision system developed ad hoc. Two efficiency parameters are defined-the significant and minimum effective boom drafts-and applied to the results of an experimental campaign involving 315 laboratory tests. Thus, the manner in which the design parameters influence the boom's efficiency under different wave and current conditions is established. PMID:19800166
Floating debris in the Mediterranean Sea.
Suaria, Giuseppe; Aliani, Stefano
Results from the first large-scale survey of floating natural (NMD) and anthropogenic (AMD) debris (>2 cm) in the central and western part of the Mediterranean Sea are reported. Floating debris was found throughout the entire study area with densities ranging from 0 to 194.6 items/km(2) and mean abundances of 24.9 AMD items/km(2) and 6.9 NMD items/km(2) across all surveyed locations. On the whole, 78% of all sighted objects were of anthropogenic origin, 95.6% of which were petrochemical derivatives (i.e. plastic and styrofoam). Maximum AMD densities (>52 items/km(2)) were found in the Adriatic Sea and in the Algerian basin, while the lowest densities (<6.3 items/km(2)) were observed in the Central Tyrrhenian and in the Sicilian Sea. All the other areas had mean densities ranging from 10.9 to 30.7 items/km(2). According to our calculations, more than 62 million macro-litter items are currently floating on the surface of the whole Mediterranean basin. PMID:25127501
Light-activated amino acid transport in Halobacterium halobium envelope vesicles
NASA Technical Reports Server (NTRS)
Macdonald, R. E.; Lanyi, J. K.
Vesicles prepared from Halobacterium halobium cell envelopes accumulate amino acids in response to light-induced electrical and chemical gradients. Nineteen of 20 commonly occurring amino acids have been shown to be actively accumulated by these vesicles in response to illumination or in response to an artificially created Na+ gradient. On the basis of shared common carriers the transport systems can be divided into eight classes, each responsible for the transport of one or several amino acids: arginine, lysine, histidine; asparagine, glutamine; alanine, glycine, threonine, serine; leucine, valine, isoleucine, methionine; phenylalanine, tyrosine, tryptophan; aspartate; glutamate; proline. Available evidence suggests that these carriers are symmetrical in that amino acids can be transported equally well in both directions across the vesicle membranes. A tentative working model to account for these observations is presented.
Liu, L.; Qian, S.-B.; Zhu, L.-Y.; He, J.-J.; Li, L.-J., E-mail: firstname.lastname@example.com [National Astronomical Observatories/Yunnan Observatory, Chinese Academy of Sciences, P.O. Box 110, 650011 Kunming (China)
The secured four-color light curves of VW Boo were analyzed with the 2003 version of the Wilson-Devinney code. It is confirmed that VW Boo is a shallow W-type contact binary system with a degree of contact factor f = 10.8%({+-} 0.5%). Two dark spots were found on the massive cool component this time. They cause an unequal depth of the two maxima. A period investigation based on all available visual, photographic, CCD, and photoelectric data shows that the period of the system includes a long-term decrease (dP/dt = -1.454 x 10{sup -7} days yr{sup -1}) and an oscillation (A{sub 3} = 0.0059 days; T{sub 3} = 25.96 years). These may be caused by mass transfer, angular momentum loss, and cyclic magnetic activity.
The effect of light quality and quantity on the flight activity of the adult hickory shuckworm Laspeyresia caryana (Fitch
Teel, Pete Don
is insensitive to exogenous stimuli until near the end of each 24-hour period. The daily flight activity of the fruit fly ~Droso hila robusta (Sturtevant) shows a close similarity to that observed for the hickory shuckworm (Roberts 1956). Flight activity... exhibited by D. robusta adults in the field became maximal just before sunset when light intensity ranged between 100 ft. -c. and 15 ft. -c. Lab- oratory investigations indicated that the occurrence of the activ- ity period was determined by a biological...
Carbon-containing nano-titania prepared by chemical vapor deposition and its visible-light-responsive photocatalytic activity
Chien-Sheng Kuo; Yao-Hsuan Tseng; Chia-Hung Huang; Yuan-Yao Li
Ultraviolet and visible-light-responsive titania was synthesized and employed in the NOx photomineralization. A thermal decomposition reaction of titanium isopropoxide was carried out with a metal-organic chemical vapor deposition (MOCVD), enabling continuous production of TiO2 nanoparticles. Carbon-containing titanium dioxide with the anatase phase prepared at 500�C under nitrogen atmosphere exhibited high photocatalytic activity for NO oxidation under visible-light illumination. Experimental results
Killing of the Yeast and Hyphal Forms of Candida albicans Using a Light-Activated Antimicrobial Agent
Z. Jackson; S. Meghji; A. MacRobert; B. Henderson; M. Wilson
.�� Oral infections due to Candida albicans are a common occurrence in patients with acquired immunodeficiency syndrome (AIDS). The purpose of this investigation was\\u000a to determine whether the yeast and hyphal forms of the organism could be killed using the light-activated antimicrobial agent\\u000a toluidine blue O (TBO). Three variables were investigated: TBO concentration, laser light dose and pre-irradiation time (PIT).
Low Power, Red, Green and Blue Carbon Nanotube Enabled Vertical Organic Light Emitting Transistors for Active Matrix OLED Displays
McCarthy, M. A. [University of Florida, Gainesville; Liu, B. [University of Florida, Gainesville; Donoghue, E. P. [University of Florida, Gainesville; Kravchenko, Ivan I [ORNL; Kim, D. Y. [University of Florida, Gainesville; So, Franky [University of Florida, Gainesville; Rinzler, A. G. [University of Florida, Gainesville
Organic semiconductors are potential alternatives to polycrystalline silicon as the semiconductor used in the backplane of active matrix organic light emitting diode displays. Demonstrated here is a light-emitting transistor with an organic channel, operating with low power dissipation at low voltage, and high aperture ratio, in three colors: red, green and blue. The single-wall carbon nanotube network source electrode is responsible for the high level of performance demonstrated. A major benefit enabled by this architecture is the integration of the drive transistor, storage capacitor and light emitter into a single device. Performance comparable to commercialized polycrystalline-silicon TFT driven OLEDs is demonstrated.
NSDL National Science Digital Library
Don Rathjen
Learn how to construct a light box by following simple figures and instructions. This guide includes tips on how to assemble a light box; related activities are featured in separate resources. Learners can assist in the building process.
Changes in sodium activity during light stimulation in photoreceptors, glia and extracellular space in drone retina.
Coles, J A; Orkand, R K
Ion-selective micro-electrodes were used to measure Na+ activity, aNa, in the two types of cell, photoreceptors and glial cells, and in the extracellular space, in superfused slices of the retina of the honey-bee drone, Apis mellifera male. Movements of Na+ were induced by light stimulation, or by increasing [K+] in the superfusate. In the dark, aNa in the photoreceptors was 10 mM (S.E. of the mean = 1 mM); in the glial cells it was higher: 37 +/- 2 mM. We estimate that in this preparation about 2/3 of the free Na+ in the tissue is in the glial cells. Stimulation with a train of light flashes, 1 s-1 for 90 s caused aNa in the photoreceptors to increase by 16 +/- 2 mM. K+ activity, aK, decreased by 21 +/- 3 mM. During the standard train of light flashes, aNa in glial cells decreased by only 1.5 +/- 0.3 mM, much less than the increase in aK (7 +/- 2 mM). One possible interpretation of this result is that most of the increase in aK is due to K+ uptake by a mechanism other than Na+-K+ exchange. In extracellular fluid, stimulation caused aNa to fall to a relatively steady value in about 10 s. Unlike aK, there was no tendency for aNa to return to the base line during the remainder of the 90 s stimulation. The fall in aNa was 14 +/- 1 mM: a greater fall is prevented by extracellular electric currents and a decrease in extracellular volume. When [K+] in the superfusate was increased from 7.5 to 18 mM, aNa decreased in the glial cells but not in the photoreceptors. In this tissue, stimulation causes changes in aNa in the neurones that might be large enough to modify the biochemistry of the cells. But in the glia, the fractional changes are small. PMID:4020694
Changes in sodium activity during light stimulation in photoreceptors, glia and extracellular space in drone retina.
Coles, J A; Orkand, R K
Ion-selective micro-electrodes were used to measure Na+ activity, aNa, in the two types of cell, photoreceptors and glial cells, and in the extracellular space, in superfused slices of the retina of the honey-bee drone, Apis mellifera male. Movements of Na+ were induced by light stimulation, or by increasing [K+] in the superfusate. In the dark, aNa in the photoreceptors was 10 mM (S.E. of the mean = 1 mM); in the glial cells it was higher: 37 +/- 2 mM. We estimate that in this preparation about 2/3 of the free Na+ in the tissue is in the glial cells. Stimulation with a train of light flashes, 1 s-1 for 90 s caused aNa in the photoreceptors to increase by 16 +/- 2 mM. K+ activity, aK, decreased by 21 +/- 3 mM. During the standard train of light flashes, aNa in glial cells decreased by only 1.5 +/- 0.3 mM, much less than the increase in aK (7 +/- 2 mM). One possible interpretation of this result is that most of the increase in aK is due to K+ uptake by a mechanism other than Na+-K+ exchange. In extracellular fluid, stimulation caused aNa to fall to a relatively steady value in about 10 s. Unlike aK, there was no tendency for aNa to return to the base line during the remainder of the 90 s stimulation. The fall in aNa was 14 +/- 1 mM: a greater fall is prevented by extracellular electric currents and a decrease in extracellular volume. When [K+] in the superfusate was increased from 7.5 to 18 mM, aNa decreased in the glial cells but not in the photoreceptors. In this tissue, stimulation causes changes in aNa in the neurones that might be large enough to modify the biochemistry of the cells. But in the glia, the fractional changes are small. PMID:4020694
Float processing of high-temperature complex silicate glasses and float baths used for same
NASA Technical Reports Server (NTRS)
Cooper, Reid Franklin (Inventor); Cook, Glen Bennett (Inventor)
A float glass process for production of high melting temperature glasses utilizes a binary metal alloy bath having the combined properties of a low melting point, low reactivity with oxygen, low vapor pressure, and minimal reactivity with the silicate glasses being formed. The metal alloy of the float medium is exothermic with a solvent metal that does not readily form an oxide. The vapor pressure of both components in the alloy is low enough to prevent deleterious vapor deposition, and there is minimal chemical and interdiffusive interaction of either component with silicate glasses under the float processing conditions. Alloys having the desired combination of properties include compositions in which gold, silver or copper is the solvent metal and silicon, germanium or tin is the solute, preferably in eutectic or near-eutectic compositions.
Floating Oil-Spill Containment Device
NASA Technical Reports Server (NTRS)
Jones, Jack A.
Previous oil containment booms have an open top that allows natural gas to escape, and have significant oil leakage due to wave action. Also, a subsea pyramid oil trap exists, but cannot move relative to moving oil plumes from deepsea oil leaks. The solution is to have large, moveable oil traps. One version floats on the sea surface and has a flexible tarp cover and a lower weighted skirt to completely entrap the floating oil and natural gas. The device must have at least three sides with boats pulling at each apex, and sonar or other system to track the slowly moving oil plume, so that the boats can properly locate the booms. The oil trap device must also have a means for removal of the oil and the natural gas. A second design version has a flexible pyramid cover that is attached by lines to ballast on the ocean floor. This is similar to fixed, metal pyramid oil capture devices in the Santa Barbara Channel off the coast of California. The ballast lines for the improved design, however, would have winches that can move the pyramid to always be located above the oil and gas plume. A third design is a combination of the first two. It uses a submerged pyramid to trap oil, but has no anchor and uses boats to locate the trap. It has ballast weights located along the bottom of the tarp and/or at the corners of the trap. The improved floating oil-spill containment device has a large floating boom and weighted skirt surrounding the oil and gas entrapment area. The device is triangular (or more than three sides) and has a flexible tarp cover with a raised gas vent area. Boats pull on the apex of the triangles to maintain tension and to allow the device to move to optimum locations to trap oil and gas. The gas is retrieved from a higher buoyant part of the tarp, and oil is retrieved from the floating oil layer contained in the device. These devices can be operated in relatively severe weather, since waves will break over the devices without causing oil leaking. Also, natural gas is entrapped and can be retrieved. All designs can use sonar to locate the moving oil plume, and then be relocated by using boats or winches to move the oil trapping devices. These devices can be constructed of treated, non-permeable DuPont Kevlar cloth (or similar material).
Macronutrients, Phytochemicals, and Antioxidant Activity of Soybean Sprout Germinated with or without Light Exposure.
Chen, Yeming; Chang, Sam K C
This study examined the macronutrients, phytochemicals, and antioxidant activities of yellow soybean sprout (YSS) and green soybean sprout (GSS) with different germination days. YSS and GSS were obtained by sprouting soybean in darkness or with light exposure at 21��C. Lipid, protein, carbohydrate, and ash contents were analyzed before and after soybean germination. Phytochemicals (total phenolic compounds, saponin, and isoflavone) were also determined. DPPH, ferric reducing antioxidant power (FRAP), and oxygen radical absorbance capacity (ORAC) were determined to examine the antioxidant activities of soybean sprout. Results showed YSS had a higher yield than GSS. Based on dry mass composition, 7-d germination of GSS decreased 14% protein, 37% lipid, 22% carbohydrate, and 16% ash, whereas 7-d germination of YSS decreased 6% protein and 47% lipid. Carbohydrate did not change and ash significantly increased for the 7-d germinated YSS. Lipid was greatly metabolized in germination, which explained why the protein relative percentage in dried soybean sprout was higher than that in the corresponding soybean. Total phenolic compounds and saponin (mg/g soybean sprout, dry basis) had the same accumulation trend in soybean sprout with the increases in germination days. Aglycone isoflavones (genistein, glycitein, and daidzein) and daidzin showed an increased trend, whereas malonylgenistin and malonylglycitin showed a decreased trend with germination days for both GSS and YSS. The change in other isoflavones did not show definite trends. GSS had 20% more antioxidant activities than YSS (7-d germinated soybean sprout). The increases in ORAC antioxidant activity suggest eating GSS may be more beneficial than GSS for promoting human health. PMID:25916398
Tank Tests of Two Floats for High-speed Seaplanes
NASA Technical Reports Server (NTRS)
Bell, Joe W
At the request of the Bureau of Aeronautics, Navy Department, a study of the design of floats especially suitable for use on high-speed seaplanes was undertaken in the N.A.C.A. tank. This note give the results obtained in tests of one-quarter full-size models of two floats for high-speed seaplanes. One was a float similar to that used on the Macchi high-speed seaplane which competed in the 1926 Schneider Trophy races, and the other a float designed at the N.A.C.A. tank in an attempt to improve on the water performance of the Macchi float. The model of the latter showed considerably better water performance than the model of the Macchi float.
Synthesis and photocatalytic activity of mesoporous cerium doped TiO{sub 2} as visible light sensitive photocatalyst
Aman, Noor [CSE Division, CSIR-National Metallurgical Laboratory, Jamshedpur 831007 (India)] [CSE Division, CSIR-National Metallurgical Laboratory, Jamshedpur 831007 (India); Satapathy, P.K. [PG Department of Chemistry, North Orissa University, Baripada 757003, Orissa (India)] [PG Department of Chemistry, North Orissa University, Baripada 757003, Orissa (India); Mishra, T., E-mail: email@example.com [CSE Division, CSIR-National Metallurgical Laboratory, Jamshedpur 831007 (India); Mahato, M. [CSE Division, CSIR-National Metallurgical Laboratory, Jamshedpur 831007 (India)] [CSE Division, CSIR-National Metallurgical Laboratory, Jamshedpur 831007 (India); Das, N.N. [PG Department of Chemistry, North Orissa University, Baripada 757003, Orissa (India)] [PG Department of Chemistry, North Orissa University, Baripada 757003, Orissa (India)
Graphical abstract: Cerium doped titania having optimum 5 wt% of cerium can decompose methylene blue and reduce selenium (IV) efficiently under visible light. Highlights: Black-Right-Pointing-Pointer Effect of cerium doping on the surface properties and visible light mediated photocatalytic reaction is studied. Black-Right-Pointing-Pointer Cerium doping increases the anatase phase stability, surface area (up to 137 m{sup 2}/g) and visible light absorption. Black-Right-Pointing-Pointer Importance of Ce{sup 3+}/Ce{sup 4+}, oxygen vacancy, surface area and crystallinity is correlated with improved catalytic activity. Black-Right-Pointing-Pointer Material with 5 wt% Ce is found to be most active photocatalyst for methylene blue decomposition and Se (IV) reduction. -- Abstract: Cerium doped titania materials were synthesized varying the cerium concentration from 0 to 10 wt%. Materials are characterised by XRD, TEM, XPS and N{sub 2} adsorption desorption method. Surface area and visible light absorption substantially increases and crystallite size decreases with the increasing cerium content. Cerium doping stabilizes the anatase phase and surface area even at 600 Degree-Sign C calcination. Photocatalytic activity towards methylene blue decomposition and selenium (IV) reduction is found to increase with the cerium content up to 5 wt% and then decreases. Materials calcined at 600 Degree-Sign C shows better activity than that calcined at 400 Degree-Sign C, even though surface area decreases. Anatase crystallinity mostly decides the photocatalytic activity rather than only surface area. It can be concluded that the optimum visible light absorption and oxygen vacancy with 5% cerium doping enhances the photocatalytic activity. In addition photocatalytic performance is found to depend on the presence of Ce{sup 4+}/Ce{sup 3+} rather than only visible light absorption.
Trident: An FPGA Compiler Framework for Floating-Point Algorithms.
Tripp J. L. (Justin L.); Peterson, K. D. (Kristopher D.); Poznanovic, J. D. (Jeffrey Daniel); Ahrens, C. M. (Christine Marie); Gokhale, M. (Maya)
Trident is a compiler for floating point algorithms written in C, producing circuits in reconfigurable logic that exploit the parallelism available in the input description. Trident automatically extracts parallelism and pipelines loop bodies using conventional compiler optimizations and scheduling techniques. Trident also provides an open framework for experimentation, analysis, and optimization of floating point algorithms on FPGAs and the flexibility to easily integrate custom floating point libraries.
Open Source High Performance Floating-Point Modules
K. Scott Hemmert; Keith D. Underwood
Given the logic density of modern FPGAs, it is feasible to use FPGAs for floating-point applications. However, it is important that any floating-point units that are used be highly optimized. This paper introduces an open source library of highly optimized floating-point units for Xilinx FPGAs. The units are fully IEEE compliant and acheive approximately 230 MHz operation frequency for double-precision
Leaf life span of floating-leaved plants
T. Tsuchiya
Photosynthetic capacity of floating-leaved plants is relatively high comparable with terrestrial herbaceous plants, though floating-leaved plants have a much smaller biomass with a leaf area index seldom exceeding 2m2m-2. Their rather small biomass accumulation is related to higher turnover of leaf biomass or shorter leaf life span. Life span of floating leaves reported in the literature ranged mostly from 13
Performance Evaluation of Decimal Floating-Point Arithmetic
Michael J. Schulte; Nick Lindberg; Anitha Laxminarain
The prominence of decimal data in commercial and financial applications has led researchers to pursue efficient techniques for performing decimal floating-point arithmetic. While several software implementations of decimal floating-point arithmetic have been implemented, there is a growing need to provide hardware support for decimal floating-point arithmetic to keep up with the processing demands of emerging commercial and financial applications. This
A combined decimal and binary floating-point divider
Sonia Gonzalez-Navarro; Alberto Nannarelli; Michael Schulte; Charles Tsen
In this paper, we present the hardware design of a combined decimal and binary floating-point divider, based on specifications in the IEEE 754-2008 Standard for Floating-point Arithmetic. In contrast to most recent decimal divider designs, which are based on the Binary Coded Decimal (BCD) encoding, our divider operates on either 64-bit binary encoded decimal floating-point (DFP) numbers or 64-bit binary
An Analysis of the Full-Floating Journal Bearing
NASA Technical Reports Server (NTRS)
Shaw, M C; Nussdorfer, T J , Jr
An analysis of the operating characteristics of a full-floating journal bearing, a bearing in which a floating sleeve is located between the journal and bearing surfaces, is presented together with charts from which the performance of such bearings may be predicted. Examples are presented to illustrate the use of these charts and a limited number of experiments conducted upon a glass full-floating bearing are reported to verify some results of the analysis.
Floating-point sparse matrix-vector multiply for FPGAs
Michael deLorimier; Andr� DeHon
Large, high density FPGAs with high local distributed memory bandwidth surpass the peak floating-point performance of high-end, general-purpose processors. Microprocessors do not deliver near their peak floating-point performance on efficient algorithms that use the Sparse Matrix-Vector Multiply (SMVM) kernel. In fact, it is not uncommon for microprocessors to yield only 10--20% of their peak floating-point performance when computing SMVM. We
Bismuth titanate microspheres: Directed synthesis and their visible light photocatalytic activity
NASA Astrophysics Data System (ADS)
Lin, Xue; Lv, Peng; Guan, Qingfeng; Li, Haibo; Zhai, Hongjv; Liu, Chunbo
Bismuth titanate, Bi4Ti3O12 (BIT), with a well-defined spherical structure, was synthesized by a facile hydrothermal process without using any surfactant or template. X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) showed that BIT spheres could be fabricated in high yields by simply manipulating the concentrations of hydroxide ions. In this case, hydroxide ions seem to play a key role in controlling the formation of seeds and growth rates of BIT particles. Ultraviolet-visible (UV-vis) absorption spectra demonstrated that the band gap of BIT samples was about 2.79 eV. In addition, based on the structural analysis of samples obtained at different conditions, a possible mechanism for the formation of these distinctive morphologies was proposed. The as-prepared BIT microspheres exhibited higher photocatalytic activities in the degradation of methyl orange (MO) under visible light irradiation than that of N-TiO2. Furthermore, BIT microspheres which prepared at OH- concentration of 3 mol L-1 showed the highest photocatalytic activity.
Controlled synthesis and visible light photocatalytic activity of Bi12GeO20 uniform microcrystals
Wan, Zhen; Zhang, Gaoke
We successfully synthesized uniform Bi12GeO20 microspheres and microtetrahedrons enclosed by four {111} facets using a controlled hydrothermal method for the first time. The photocatalytic activity of these regular-shaped products was further investigated by the degradation of RhB and gaseous formaldehyde under visible light irradiation (?>420?nm). The Bi12GeO20 microtetrahedrons (s) exhibited enhanced photocatalytic activity and stability which is closely related to the high capacity of exposed {111} facets for uptake of O2. The formation mechanism studies indicate that the Bi12GeO20 seeds were directed to grow into truncated microcubes, truncated microtetrahedrons, and then microtetrahedrons when the NaOH concentration was 5?M. The same batch of seeds only evolved into microspheres when the NaOH concentration was switched to 3?M. The difference in Bi12GeO20 morphology could be attributed to the rates of both crystal nucleation and crystal growth. PMID:25199641
Floating drug delivery of nevirapine as a gastroretentive system.
Vedha, Hari Bn; Brahma, Reddy A; Samyuktha, Rani B
A multiple-unit floating drug delivery system based on gas formation technique was developed, in order to prolong the gastric residence time and to increase the overall bioavailability of the dosage form. The floating bead formulations were prepared by dispersing nevirapine together with calcium carbonate in a mixture of sodium alginate and hydroxypropyl methylcellulose solution and then dripping the dispersion into an acidified solution of calcium chloride. Calcium alginate beads were formed, as the alginate underwent ionotropic gelation by calcium ions, and carbon dioxide developed from the reaction of carbonate salts with acid. The obtained beads were able to float due to CO(2)-gas formation and the gas entrapment by the polymeric membrane. The prepared beads were evaluated for percent drug loading, drug entrapment efficiency, morphology, surface topography, buoyancy, in-vitro release, and release kinetics. The formulations were optimized for different weight ratios of the gas-forming agent and sodium alginate. The beads containing higher amounts of calcium carbonate demonstrated an instantaneous, complete, and excellent floating ability over a period of 24 hours. The increased amount of the gas forming agent did not affect the time to float, but increased the drug release from the floating beads, while increasing the coating level of the gas-entrapped membrane, increased the time to float, and slightly retarded the drug release. Good floating properties and sustained drug release were achieved. Finally, these floating beads seemed to be a promising gastroretentive drug delivery system. PMID:21264092
Characterization and improved solar light activity of vanadium doped TiO2/diatomite hybrid catalysts.
Wang, Bin; Zhang, Guangxin; Leng, Xue; Sun, Zhiming; Zheng, Shuilin
V-doped TiO2/diatomite composite photocatalysts with different vanadium concentrations were synthesized by a modified sol-gel method. The diatomite was responsible for the well dispersion of TiO2 nanoparticles on the matrix and consequently inhibited the agglomeration. V-TiO2/diatomite hybrids showed red shift in TiO2 absorption edge with enhanced absorption intensity. Most importantly, the dopant energy levels were formed in the TiO2 bandgap due to V(4+) ions substituted to Ti(4+) sites. The 0.5% V-TiO2/diatomite photocatalyst displayed narrower bandgap (2.95 eV) compared to undoped sample (3.13 eV) and other doped samples (3.05 eV) with higher doping concentration. The photocatalytic activities of V doped TiO2/diatomite samples for the degradation of Rhodamine B under stimulated solar light illumination were significantly improved compared with the undoped sample. In our case, V(4+) ions incorporated in TiO2 lattice were responsible for increased visible-light absorption and electron transfer to oxygen molecules adsorbed on the surface of TiO2 to produce superoxide radicals ?O2(-), while V(5+) species presented on the surface of TiO2 particles in the form of V2O5 contributed to e(-)-h(+) separation. In addition, due to the combination of diatomite as support, this hybrid photocatalyst could be separated from solution quickly by natural settlement and exhibited good reusability. PMID:25497036
Action spectrum of oxidative reactions mediated by light-activated melanin
NASA Astrophysics Data System (ADS)
Glickman, Randolph D.; Rockwell, Benjamin A.; Jacques, Steven L.
The melanin of the retinal pigment epithelial (RPE) cells is generally thought to have a photoprotective role in the eye, yet it is excited by light to a free radical which can react with cellular components. Soluble proteins extracted from the retina are photo-oxidized by the output of a Xenon arc lamp containing UVA and visible wavelengths. The oxidative damage in this model consists of carbonyl adducts to the peptides, and is proportional to the amount of UVA present. Melanosomes isolated from bovine RPE cells and added to the retinal protein extract partly protect the proteins from photo-oxidation resulting from this broadband exposure. However, if the proteins are instead exposed to the 488 and 514.5 nm outputs of an Argon continuous wave laser, the amount of protein oxidation is markedly increased when melanosomes are present. This observation suggests that the melanin free radical is optimally excited by wavelengths in the blue-green region of the visible spectrum, and in fact the action spectrum for the photo-oxidation of NADPH by laser-excited melanin peaks between 450 and 500 nm. The present data do not distinguish between two alternative hypotheses, i.e. that the apparent action spectrum peak is due to (1) a chromophore different from the one determining the overall optical absorption of melanin, or (2) the lower efficiency of UVA photons in activating melanosomes because of their strong absorption at the solution surface. Nevertheless these data implicate melanin in the so-called 'blue light' retinal hazard.
The cryptoendolithic microbial environment in the Ross Desert of Antarctica: Light in the photosynthetically active region
James A. Nienow; Christopher P. McKay; E. Imre Friedmann
The vertical zonation of the Antarctic cryptoendolithic community appears to form in response to the light regime in the habitat. However, because of the structure of the habitat, the light regime is difficult to study directly. Therefore, a mathematical model of the light regime was constructed, which was used to estimate the total photon flux in different zones of the
Human Cryptochrome-1 Confers Light Independent Biological Activity in Transgenic Drosophila Correlated
Paris-Sud XI, Universit� de
and entrainment of the circadian clock in animals. Light perception is proposed to occur through flavin radical, mammalian (Type II) cryptochromes regulate the circadian clock independently of light, raising sequence and structural homology to photolyases, a class of light sensing DNA repair enzyme. Cryptochromes
Development of bilayer floating tablet of amoxicillin and Aloe vera gel powder for treatment of gastric ulcers.
Ranade, Arati N; Wankhede, Sonali S; Ranpise, Nisharani S; Mundada, Mayur S
Usual treatment for Helicobacter pylori-induced peptic ulcer includes a 'triple therapy' consisting of two antibiotics (amoxicillin and clarithromycin) and a proton pump inhibitor (omeprazole). The objective of this project work was defined with a view to retain the drug in stomach for better antiulcer activity and substituting one of the synthetic drugs in this therapy with a herbal alternative. Hence, aim of the present work was to design and develop a bilayer floating tablet of amoxicillin and Aloe vera gel powder for the treatment of peptic ulcer. A. vera gel powder is used for its cytoprotective action. Bilayer floating tablets were prepared by applying direct compression technique. The proportion of sodium bicarbonate and citric acid was adjusted to get the least possible lag time with good matrix integrity and total floating time. Polymer concentration was adjusted to get the maximum release in 8�h. The formulation was developed using hydroxypropyl methyl cellulose (HPMC) K4M and HPMC K100M in a ratio of 85:15 along with 1:4 ratio of effervescent agents was found to give floating lag time of less than 1�min with total floating time of more than 8�h and 97.0% drug release in 8�h. In vivo study in rats meets the requirement of antiulcer activity for bilayer tablet in comparison to single amoxicillin as standard. PMID:23135966
33 CFR 147.815 - ExxonMobil Hoover Floating OCS Facility safety zone.
Code of Federal Regulations, 2013 CFR
...2013-07-01 false ExxonMobil Hoover Floating OCS Facility safety zone. 147... � 147.815 ExxonMobil Hoover Floating OCS Facility safety zone. (a) Description. The ExxonMobil Hoover Floating OCS Facility, Alaminos Canyon...
33 CFR 147.815 - ExxonMobil Hoover Floating OCS Facility safety zone.
Code of Federal Regulations, 2014 CFR
...2014-07-01 false ExxonMobil Hoover Floating OCS Facility safety zone. 147... � 147.815 ExxonMobil Hoover Floating OCS Facility safety zone. (a) Description. The ExxonMobil Hoover Floating OCS Facility, Alaminos Canyon...
33 CFR 147.815 - ExxonMobil Hoover Floating OCS Facility safety zone.
Code of Federal Regulations, 2012 CFR
...2012-07-01 false ExxonMobil Hoover Floating OCS Facility safety zone. 147... � 147.815 ExxonMobil Hoover Floating OCS Facility safety zone. (a) Description. The ExxonMobil Hoover Floating OCS Facility, Alaminos Canyon...
33 CFR 146.104 - Safety and Security notice of arrival for foreign floating facilities.
Code of Federal Regulations, 2014 CFR
...Security notice of arrival for foreign floating facilities. 146.104 Section...Security notice of arrival for foreign floating facilities. (a) General. At least 96 hours before a foreign floating facility arrives on the OCS...
33 CFR 147.815 - ExxonMobil Hoover Floating OCS Facility safety zone.
Code of Federal Regulations, 2010 CFR
...2010-07-01 false ExxonMobil Hoover Floating OCS Facility safety zone. 147... � 147.815 ExxonMobil Hoover Floating OCS Facility safety zone. (a) Description. The ExxonMobil Hoover Floating OCS Facility, Alaminos Canyon...
76 FR 52638 - Proposed Information Collection; Comment Request; Shipboard Observation Form for Floating Marine...
Federal Register 2010, 2011, 2012, 2013, 2014
...Request; Shipboard Observation Form for Floating Marine Debris AGENCY: National Oceanic...The Shipboard Observation Form for Floating Marine Debris was created based on methods used in studies of floating marine debris by established...
33 CFR 146.104 - Safety and Security notice of arrival for foreign floating facilities.
Code of Federal Regulations, 2013 CFR
...Security notice of arrival for foreign floating facilities. 146.104 Section...Security notice of arrival for foreign floating facilities. (a) General. At least 96 hours before a foreign floating facility arrives on the OCS...
33 CFR 146.104 - Safety and Security notice of arrival for foreign floating facilities.
Code of Federal Regulations, 2011 CFR
...Security notice of arrival for foreign floating facilities. 146.104 Section...Security notice of arrival for foreign floating facilities. (a) General. At least 96 hours before a foreign floating facility arrives on the OCS...
33 CFR 147.815 - ExxonMobil Hoover Floating OCS Facility safety zone.
Code of Federal Regulations, 2011 CFR
...2011-07-01 false ExxonMobil Hoover Floating OCS Facility safety zone. 147... � 147.815 ExxonMobil Hoover Floating OCS Facility safety zone. (a) Description. The ExxonMobil Hoover Floating OCS Facility, Alaminos Canyon...
33 CFR 146.104 - Safety and Security notice of arrival for foreign floating facilities.
Code of Federal Regulations, 2012 CFR
...Security notice of arrival for foreign floating facilities. 146.104 Section...Security notice of arrival for foreign floating facilities. (a) General. At least 96 hours before a foreign floating facility arrives on the OCS...
Mooring Line Modelling and Design Optimization of Floating Offshore Wind Turbines
Victoria, University of
Mooring Line Modelling and Design Optimization of Floating Offshore Wind Turbines by Matthew Thomas Mooring Line Modelling and Design Optimization of Floating Offshore Wind Turbines by Matthew Thomas Jair. Curran Crawford, Supervisor (Department of Mechanical Engineering) ABSTRACT Floating offshore wind
Carrier Injections in Nitride-Based Light Emitting Diodes Including Two Active Regions with Mg-Doped Intermediate Layers
NASA Astrophysics Data System (ADS)
Matsui, Kenjo; Yamashita, Koji; Kaga, Mitsuru; Morita, Takatoshi; Suzuki, Tomoyuki; Takeuch, Tetsuya; Kamiyama, Satoshi; Iwaya, Motoaki; Akasaki, Isamu
We achieved simultaneous two emissions from a single light emitting diode containing violet and blue GaInN/GaN quantum well active regions separated with an intermediate layer. By adjusting a thickness of a Mg-doped region in the intermediate layer, an intensity ratio between violet and blue emissions was changed, caused by different carrier distributions in the two active regions. The intensity ratio from two active regions was also changed by changing an amount of current injection. An unintentional Mg incorporation into the active region above the Mg-doped intermediate layer was observed, which is due to Mg memory effect.
The difference between �giving a rose� and �giving a kiss�: Sustained neural activity to the light verb construction
Wittenberg, Eva; Paczynski, Martin; Wiese, Heike; Jackendoff, Ray; Kuperberg, Gina
We used event-related potentials (ERPs) to investigate the neurocognitive mechanisms associated with processing light verb constructions such as �give a kiss�. These constructions consist of a semantically underspecified light verb (�give�) and an event nominal that contributes most of the meaning and also activates an argument structure of its own (�kiss�). This creates a mismatch between the syntactic constituents and the semantic roles of a sentence. Native speakers read German verb-final sentences that contained light verb constructions (e.g., �Julius gave Anne a kiss�), non-light constructions (e.g., �Julius gave Anne a rose�), and semantically anomalous constructions (e.g., *�Julius gave Anne a conversation�). ERPs were measured at the critical verb, which appeared after all its arguments. Compared to non-light constructions, the light verb constructions evoked a widely distributed, frontally focused, sustained negative-going effect between 500 and 900 ms after verb onset. We interpret this effect as reflecting working memory costs associated with complex semantic processes that establish a shared argument structure in the light verb constructions. PMID:24910498
The impact of floating migration on fertility in China: are floating migrants "childbearing guerillas"?
You, Xiuhong
who live at a place other than their place of household registration. Floating migrants are further distinguished by long term and short term according to the time length after migration. They are also studied in terms of their origins and directions...
TiO{sub 2}/carbon nanotube hybrid nanostructures: Solvothermal synthesis and their visible light photocatalytic activity
Tian Lihong [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062 (China); Ye Liqun [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Deng Kejian [Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, South-Central University for Nationalities, Wuhan 430074 (China); Zan Ling, E-mail: email@example.com [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China)
MWCNT/TiO{sub 2} hybrid nanostructures were prepared via solvothermal synthesis and sol-gel method with benzyl alcohol as a surfactant. As-prepared hybrid materials were characterized by X-ray diffraction, transmission electron microscopy, UV-vis diffuse reflectance spectra and X-ray photoelectron spectroscopy. The results showed that MWCNTs were uniformly decorated with anatase nanocrystals in solvothermal condition, but MWCNTs were embedded in a majority of TiO{sub 2} nanoparticles by sol-gel method. When the weight ratio of MWCNTs to TiO{sub 2} was 20%, MWCNT/TiO{sub 2} hybrid nanostructures prepared by solvothermal synthesis exhibited higher visible-light-driven photocatalytic activity than that prepared by sol-gel method. Post-annealing of MWCNT/TiO{sub 2} nanostructures at 400 deg. C resulted in the formation of the carbonaceous Ti-C bonds on the interface between TiO{sub 2} and MWCNTs, which enhanced the photoabsorbance of the hybrid materials in the visible light region and improved the visible-light degradation efficiency of methylene blue. - Graphical abstract: MWCNT/TiO{sub 2} nanostructures have been prepared by solvothermal method, which exhibited higher visible-light-driven photocatalytic activity than that prepared by sol-gel method. The carbonaceous Ti-C bonds on the interface between TiO{sub 2} and MWCNTs enhanced the photoabsorbance of the hybrid materials in the visible light region. Highlights: > Anatase TiO{sub 2} nanoparticles were anchored on CNTs surface uniformly via solvothermal method {yields} The morphology facilitated the electron transfer between CNTs and TiO{sub 2} {yields} Ti-C bonds extended the absorption of MWCNT/TiO{sub 2} to the whole visible light region. > The hybrid nanostructures showed enhanced visible-light induced photocatalytic activity.
Floating production unit to work off Brazil
Not Available
This paper reports that Petroleo Brasileiro SA expects by early November to deploy its Petrobras XXIV floating production unit (FPU) in about 900 ft of water in Albacora field off Brazil. The FPU was scheduled to depart Galveston, Tex., this month, following completion of modifications and upgrades under a turnkey contract with Chiles Offshore International Inc. Chiles began modifying Petrobras XXIV about 1 year ago as part of a deal closed in October 1991 in which Chiles Offshore Corp. sold the vessel, then known as Intrepid, to Brasoil, the international subsidiary of Petrobras.
Floating hydrometer with energy dissipating baffle
Kownurko, W.A.
This patent describes a floating hydrometer employable for purposes of obtaining measurements of the presence of suspended solids in a fluid substance contained in a receptacle comprising: a. a probe portion operative as an instrument-bearing housing; b. an elongated tubular element having a hollow interior and at least one open end so as to enable the flow into the hollow interior of the elongated tubular element through the open end; and c. energy dissipating baffle means having a first mode of action and a second mode of action and including a member having a hollow interior.
BRIEF COMMUNICATIONS: Generation of light pulses of 40-ps duration in a YAG:Nd laser with active mode locking
V. Kabelka; R. Kondrotas; V. D. Ligun; L. N. Matveev; A. Milyauskas; S. I. Chizhikov
Minimum durations of light pulses generated in YAG:Nd lasers with active mode locking can be achieved by increasing the efficiency of operation of an acousto-optic switch. It is reported that a new material in the form of a CaMoO4 single crystal can be used as the acoustic guide in the switch. Application of this switch in active mode locking in
Biological activity of designed photolabile metal nitrosyls: light-dependent activation of soluble guanylate cyclase and vasorelaxant properties in rat aorta.
Madhani, Melanie; Patra, Apurba K; Miller, Thomas W; Eroy-Reveles, Aura A; Hobbs, Adrian J; Fukuto, Jon M; Mascharak, Pradip K
The biological and pharmacological utility of nitric oxide (NO) has led to the development of many classes of NO-donor compounds as both research tools and therapeutic agents. Many donors currently in use rely on thermal decomposition or bioactivation for the release of NO. We have developed several photolabile metal-nitrosyl donors that release NO when exposed to either visible or UV light. Herein, we show that these donors are capable of activating the primary "NO receptor", soluble guanylate cyclase (sGC), in a light-dependent fashion leading to increases in cGMP. Moreover, we demonstrate that these donors are capable of eliciting light-dependent increases of cGMP in smooth muscle cells and vasorelaxation of rat aortic smooth muscle tissue, all effects that are attributed to activation of sGC. The potential utility of these compounds as drugs and/or research tools is discussed. PMID:17149862
What every computer scientist should know about floating-point arithmetic
David Goldberg
Floating-point arithmetic is considered as esoteric subject by many people. This is rather surprising, because floating-point is ubiquitous in computer systems: Almost every language has a floating-point datatype; computers from PCs to supercomputers have floating-point accelerators; most compilers will be called upon to compile floating-point algorithms from time to time; and virtually every operating system must respond to floating-point exceptions
Light regulation of peroxidase activity by spiropyran functionalized carbon nanotubes used for label-free colorimetric detection of lysozyme.
Song, Yujun; Xu, Can; Wei, Weili; Ren, Jinsong; Qu, Xiaogang
Spiropyran dye-modified multi-walled carbon nanotubes have been synthesized and used to regulate horseradish peroxidase activity by light irradiation. This design has been developed for a label-free colorimetric assay of lysozyme with a direct detection limit of 30 nM. PMID:21748199
Dye Surface Coating Enables Visible Light Activation of TiO2 Nanoparticles Leading to Degradation of
Brown, Eric
Dye Surface Coating Enables Visible Light Activation of TiO2 Nanoparticles Leading to Degradation, University of Wisconsin-Whitewater, Whitewater, WI 53190, USA 2 Division of Functional Materials and Nano Devices, Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology
Recoverable Residual Image Induced by Hysteresis of Thin Film Transistors in Active Matrix Organic Light Emitting Diode Displays
Byeong-Koo Kim; Ohyun Kim; Hoon-Ju Chung; Jae-Won Chang; Yong-Min Ha
A recoverable residual image is observed and analyzed in voltage driven active matrix organic light emitting diode (AMOLED) displays of which pixel circuits consist of two thin film transistors (TFTs) and one capacitor. The cause of the residual image is proven to be the hysteresis of the driving TFT in the pixel. The hysteresis of the p-channel TFT can be
67P/Churyumov-Gerasimenko: start of activity and heliocentric light curve
NASA Astrophysics Data System (ADS)
Tubiana, C.; Snodgrass, C.; Bramich, D.; Boehnhardt, H.; Barrera, L.
Comets are believed to be widely unmodified remnants from the formation of the solar system; their study can give important insights into the conditions prevailing at the time of the planetary system formation. After the success of the Giotto mission to comet 1P/Halley, the European Space Agency (ESA) approved in the early nineties a new space mission with a comet as main target: Rosetta, which will rendezvous with come 67P/Churyumov-Gerasimenko (67P/C-G) in 2014. 67P/C-G is a Jupiter family comet with orbital period of 6.56 years. Due to repeated encounters with Jupiter, the orbital evolution of 67P/C-G is chaotic. The last encounter in February 1959 occurred at a distance of only 0.0518 AU and produced drastic changes in perihelion distance, eccentricity, inclination, orbital period and possibly led to its discovery in 1969. After 67P/C-G was selected as target comet of Rosetta mission, observational campaigns and theoretical investigations were performed in order to establish a detailed portrait of 67P/C-G in preparation of the rendezvous with the spacecraft ([1], [2], [3], [4]). Here we present ground-based observations of 67P/CG obtained between July 2007 and March 2008 at ESO VLT using the FORS2 instrument. The comet was moving inbound, from 4.6 AU to 3.4 AU. The orbital arc covered by our observation is the same where 67P/C-G will be in 2014 when the rendezvous with the Rosetta spacecraft will take place, thus of highly interest for mission planning. Since the comet's activity around perihelion has shown similar behaviour during the last three orbital passages, it is fair to assume that the comet's behavior at large heliocentric distance has not changed from one orbital revolution to the other, leading us to expect that during its approach to 67P/CG, Rosetta will find the same conditions detected during our observations. A considerable difficulty in observing 67P/C-G during the past years has been its position against crowded fields towards the galactic centre for much of this time (Fig. 1 - top). The 2007/8 data presented here was particularly difficult, and the comet will once again be badly placed for Earth based observations in 2014/5. We made use of the technique of Difference Image Analysis (as implemented in the DanDIA software, [5]), which is commonly used in variable star and exoplanet research, to remove background sources and extract images of the comet (Fig. 1 - bottom). We determined that the comet became active during the period November 2007 - March 2008, at a distance of 4.1-3.4 AU from the Sun. The comet will reach this distance, and probably become active again, in April- September 2014. To investigate the longer period activity cycle of the comet we compiled the heliocentric light curve of the comet, making use of images of 67P/C-G taken during the last three apparitions taken from the ESO archive. A preliminary light curve is shown in 2. This information will be used for planning observing campaigns, both from the ground and using OSIRIS on board Rosetta.
Light-activated nanotube-porphyrin conjugates as effective antiviral agents
NASA Astrophysics Data System (ADS)
Banerjee, Indrani; Douaisi, Marc P.; Mondal, Dhananjoy; Kane, Ravi S.
Porphyrins have been used for photodynamic therapy (PDT) against a wide range of targets like bacteria, viruses and tumor cells. In this work, we report porphyrin-conjugated multi-walled carbon nanotubes (NT-P) as potent antiviral agents. Specifically, we used Protoporphyrin IX (PPIX), which we attached to acid-functionalized multi-walled carbon nanotubes (MWNTs). We decided to use carbon nanotubes as scaffolds because of their ease of recovery from a solution through filtration. In the presence of visible light, NT-P was found to significantly reduce the ability of Influenza A virus to infect mammalian cells. NT-P may be used effectively against influenza viruses with little or no chance of them developing resistance to the treatment. Furthermore, NT-P can be easily recovered through filtration which offers a facile strategy to reuse the active porphyrin moiety to its fullest extent. Thus NT-P conjugates represent a new approach for preparing ex vivo reusable antiviral agents.
Optimal parameters for arterial repair using light-activated surgical adhesives.
Soller, Eric C; Hoffman, Grant T; McNally-Heintzelman, Karen M
The clinical acceptance of laser-tissue repair techniques is dependent on the reproducibility of viable repairs. Reproducibility is dependent on two factors: (i) the choice of materials to be used as the adhesive; and (ii) obtaining temperatures high enough to cause protein denaturation at the vital tissue interface without causing excessive thermal damage to the surrounding tissue. The use of a polymer scaffold as a carrier for the protein solder provides for uniform application of the solder to the tissue, thus allowing for pre-selection of optimal laser parameters. The scaffold also facilitates precise tissue alignment and ease of clinical application. In addition, the scaffold can be doped with various pharmaceuticals such as hemostatic and thrombogenic agents to aid wound healing. An ex vivo study was performed to correlate solder and tissue temperature with the tensile strength of arterial repairs formed using scaffold-enhanced light-activated surgical adhesives. Previous studies by our group using solid protein solder without the scaffold indicate that a solder/tissue, interface temperature of 65 degrees C is optimal. Using this parameter as a benchmark, laser irradiance was varied and temperatures were recorded at the surface and at the tissue interface of scaffold-enhanced protein solder using an infrared temperature monitoring system, designed by the researchers, and a type-K thermocouple, respectively. PMID:12724862
Light activity following a meal and postprandial cardiometabolic risk in adolescents.
Sisson, Susan B; Anderson, Ashley E; Short, Kevin R; Gardner, Andrew W; Whited, Teresa; Robledo, Candace; Thompson, David M
The purpose of this study was to determine if light physical activity (LPA) minimizes the impairment of cardiometabolic risk factors following a typical meal in adolescents. Eighteen adolescents (50% male, 14.8 � 2.3 yrs) consumed a meal (32% fat, 14% protein, 53% carbohydrate), then completed a walking (1.5 mph for 45 min of each hour) or sitting treatment for 3 hr in randomized order on separate days. Following the meal, HDL cholesterol declined 4.8% but remained higher during walking at 3 hr (42.1 mg/dl � 9.3) than sitting (8.4% decline; 40.5 mg/dL � 9.9; treatment x time interaction, p < .03). The 3-hr insulin was lower after walking (24.8 ?IU/ml � 33.4) than sitting (37.8 ?IU/ml � 34.7; treatment x time interaction, p < .0001). Triglycerides increased by ~40% above baseline at 1 and 2 hr, with higher values for walking (treatment x time interaction, p < .02). However by 3 hr, triglycerides were not different from baseline. Area under the curve (AUC) analyses were not significantly different between treatments for any outcomes. Although minor, LPA appears to mitigate the undesirable postprandial changes in HDL cholesterol and insulin but not triglycerides, following a typical meal in adolescents. PMID:23501926